With MediaPlayer1 do begin
     Filename := sWinDir + 'Clock.avi'; //specify video file
     DeviceType := dtAVIVideo; //set Device compatibility to AVI
     Display := Panel1; //Set display device to a TPanel
     Open;
     Play;
end;

위의 코드처럼 해 보세요...

아마도 open이나 Display := Panel1 이것을 안해서 일겁니다.

MCI 장치 -비디오,오디오 장치가
사용중이거나 없다는 이야기입니다.

아래 내용이 도움이 될런지요?

Here is the list from the manual

  
  5000 - MCIERR_SUCCESS
      MMPM/2 command completed successfully.

  5001 - MCIERR_INVALID_DEVICE_ID
      Invalid device ID given.

  5002 - MCIERR_NO_MASTER
      Unable to find a Master.

  5003 - MCIERR_UNRECOGNIZED_KEYWORD
      Unrecognized keyword given in command string.

  5004 - MCIERR_MASTER_CONFLICT
      Only one device can be a Master.

  5005 - MCIERR_UNRECOGNIZED_COMMAND
      Unrecognized command.

  5006 - MCIERR_HARDWARE
      Hardware error.

  5007 - MCIERR_INVALID_DEVICE_NAME
      Invalid Device Name given.

  5008 - MCIERR_OUT_OF_MEMORY
      System out of memory.

  5009 - MCIERR_DEVICE_OPEN
      Device is already open.

  5010 - MCIERR_CANNOT_LOAD_DRIVER
      Cannot load MMPM/2 driver.

  5011 - MCIERR_MISSING_COMMAND_STRING
      Missing command string.

  5012 - MCIERR_PARAM_OVERFLOW
      Parameter overflow.

  5013 - MCIERR_MISSING_STRING_ARGUMENT
      Missing required string argument.

  5014 - MCIERR_BAD_INTEGER
      Bad integer given in command string.

  5015 - MCIERR_PARSER_INTERNAL
      Internal MMPM/2 parser error.

  5016 - MCIERR_DRIVER_INTERNAL
      Internal MMPM/2 driver error.

  5017 - MCIERR_MISSING_PARAMETER
      Missing parameter for this command.

  5018 - MCIERR_UNSUPPORTED_FUNCTION
      Function not supported by the media control driver being used.

  5019 - MCIERR_FILE_NOT_FOUND
      File not found.

  5020 - MCIERR_DEVICE_NOT_READY
      Device is not ready.

  5021 - MCIERR_INTERNAL
      MMPM/2 internal error.

  5022 - MCIERR_DRIVER
      Internal MMPM/2 driver error.

  5023 - MCIERR_CANNOT_USE_ALL
      Cannot use ALL keyword with this command.

  5024 - MCIERR_MULTIPLE
      Multiple defined.

  5025 - MCIERR_EXTENSION_NOT_FOUND
      Extension not found.

  5026 - MCIERR_OUTOFRANGE
      Value given is out of range.

  5027 - MCIERR_CANNOT_ADD_ALIAS
      Cannot add alias.

  5028 - MCIERR_FLAGS_NOT_COMPATIBLE
      Flags not compatible.

  5029 - MCIERR_CANNOT_USE_NOUNLOAD
      Cannot use NOUNLOAD flag with this command.

  5030 - MCIERR_FILE_NOT_SAVED
      File not saved.

  5031 - MCIERR_DEVICE_TYPE_REQUIRED
      Device type required.

  5032 - MCIERR_DEVICE_LOCKED
      Device is locked.

  5033 - MCIERR_DUPLICATE_ALIAS
      Duplicate alias.

  5034 - MCIERR_INSTANCE_INACTIVE
      Instance inactive.

  5035 - MCIERR_COMMAND_TABLE
      Command table error.

  5037 - MCIERR_INI_FILE_LOCKED
      The MMPM2.INI file is currently locked.

  5040 - MCIERR_NO_AUDIO_SUPPORT
      No audio support present.

  5041 - MCIERR_NOT_IN_PM_SESSION
      Not currently in a Presentation Manager Session.

  5042 - MCIERR_DUPLICATE_KEYWORD
      Duplicate keyword in command string.

  5043 - MCIERR_COMMAND_STRING_OVERFLOW
      Command string too long.

  5044 - MCIERR_DRIVER_PROC_NOT_FOUND
      MMPM/2 driver procedure address not found.

  5045 - MCIERR_INVALID_DEVICE_TYPE
      Invalid device type given.

  5046 - MCIERR_INVALID_DEVICE_ORDINAL
      Invalid device ordinal given.

  5047 - MCIERR_HEADPHONES_NOT_SET
      Headphones not set on.

  5048 - MCIERR_SPEAKERS_NOT_SET
      Speakers not set on.

  5049 - MCIERR_SOUND_NOT_SET
      Mute on.

  5050 - MCIERR_INVALID_BUFFER
      Invalid return buffer given.

  5051 - MCIERR_INVALID_MEDIA_TYPE
      Invalid media type given.

  5052 - MCIERR_INVALID_CONNECTOR_INDEX
      Invalid connector index.

  5053 - MCIERR_NO_CONNECTION
      No connection found.

  5054 - MCIERR_INVALID_FLAG
      Invalid flag specified for this command.

  5055 - MCIERR_CANNOT_LOAD_DSP_MOD
      DSP module not found.

  5056 - MCIERR_ALREADY_CONNECTED
      The connection already exists.

  5057 - MCIERR_INVALID_CALLBACK_HANDLE
      The window callback handle is invalid.

  5058 - MCIERR_DRIVER_NOT_FOUND
      MMPM2 driver not found.

  5059 - MCIERR_DUPLICATE_DRIVER
      Duplicate MMPM/2 driver found.

  5060 - MCIERR_INI_FILE
      MMPM2.INI file error.

  5061 - MCIERR_INVALID_GROUP_ID
      Invalid group ID given.

  5062 - MCIERR_ID_ALREADY_IN_GROUP
      Device ID already in group.

  5063 - MCIERR_MEDIA_CHANGED
      Media has been changed.

  5064 - MCIERR_MISSING_FLAG
      Flag missing for this MMPM/2 command.

  5065 - MCIERR_UNSUPPORTED_FLAG
      Flag not supported by this MMPM/2 driver for this command.

  5066 - MCIERR_DRIVER_NOT_LOADED
      MMPM/2 driver is not loaded.

  5067 - MCIERR_INVALID_MODE
      Device mode is invalid for this command.

  5068 - MCIERR_INVALID_ITEM_FLAG
      Invalid item flag specified for this command.

  5069 - MCIERR_INVALID_TIME_FORMAT_FLAG
      Invalid time format flag specified for this command.

  5070 - MCIERR_SPEED_FORMAT_FLAG
      Invalid speed format flag specified for this command.

  5071 - MCIERR_INVALID_AUDIO_FLAG
      Invalid audio flag specified for this command.

  5072 - MCIERR_NODEFAULT_DEVICE
      No default device specified.

  5073 - MCIERR_DUPLICATE_EXTENSION
      Duplicate Extension specified.

  5074 - MCIERR_FILE_ATTRIBUTE
      File Attribute error specified.

  5075 - MCIERR_DUPLICATE_CUEPOINT
      Duplicate cuepoint given.

  5076 - MCIERR_INVALID_CUEPOINT
      Invalid cuepoint given.

  5077 - MCIERR_CUEPOINT_LIMIT_REACHED
      Cue-point limit reached.

  5078 - MCIERR_MISSING_ITEM
      Item flag missing for this command.

  5079 - MCIERR_MISSING_TIME_FORMAT
      Time format flag missing for this command.

  5080 - MCIERR_MISSING_SPEED_FORMAT
      Speed format flag missing for this command.

  5081 - MCIERR_INVALID_CONNECTOR_TYPE
      Invalid connector type given.

  5082 - MCIERR_TARGET_DEVICE_FULL
      Target device is full.

  5083 - MCIERR_UNSUPPORTED_CONN_TYPE
      Connector type is not supported by this device.

  5084 - MCIERR_CANNOT_MODIFY_CONNECTOR
      Cannot enable or disable this connector.

  5085 - MCIERR_RECORD_ABORTED
      Record has been aborted.

  5086 - MCIERR_GROUP_COMMAND
      One or more devices in group failed command.

  5087 - MCIERR_DEVICE_NOT_FOUND
      Device cannot be found.

  5088 - MCIERR_RESOURCE_NOT_AVAILABLE
      Device resource is not available.

  5089 - MCIERR_INVALID_IO_PROC
      Invalid MMIO I/O procedure given.

  5090 - MCIERR_WAVE_OUTPUTSINUSE
      Output is in use.

  5091 - MCIERR_WAVE_SETOUTPUTINUSE
      Output is in use.

  5092 - MCIERR_WAVE_INPUTSINUSE
      Input is in use.

  5093 - MCIERR_WAVE_SETINPUTINUSE
      Input is in use.

  5094 - MCIERR_WAVE_OUTPUTUNSPECIFIED
      Output not specified.

  5095 - MCIERR_WAVE_INPUTUNSPECIFIED
      Input not specified.

  5096 - MCIERR_WAVE_OUTPUTSUNSUITABLE
      Output is not suitable.

  5097 - MCIERR_WAVE_SETOUTPUTUNSUITABLE
      Output is not suitable.

  5098 - MCIERR_WAVE_INPUTSUNSUITABLE
      Input is not suitable.

  5099 - MCIERR_WAVE_SETINPUTUNSUITABLE
      Input is not suitable.

  5100 - MCIERR_SEQ_DIV_INCOMPATIBLE
      Division format is not compatable with this device.

  5101 - MCIERR_SEQ_PORT_INUSE
      Port in use.

  5102 - MCIERR_SEQ_PORT_NONEXISTENT
      Port does not exist for this device.

  5103 - MCIERR_SEQ_PORT_MAPNODEVICE
      MIDI mapper device does not exist.

  5104 - MCIERR_SEQ_PORT_MISCERROR
      Port error.

  5105 - MCIERR_SEQ_TIMER
      MIDI timer error.

  5106 - MCIERR_VDP_COMMANDCANCELLED
      MMPM/2 command was cancelled by another MCI command.

  5107 - MCIERR_VDP_COMMANDFAILURE
      MMPM/2 command failed.

  5108 - MCIERR_VDP_NOTSPUNUP
      MMPM/2 command requires the videodisc player to be spun up.

  5109 - MCIERR_VDP_NOCHAPTER
      MMPM/2 command requires the videodisc to have chapters.

  5110 - MCIERR_VDP_NOSIDE
      Videodisc side cannot be determined.

  5111 - MCIERR_VDP_NOSIZE
      Videodisc size cannot be determined.

  5112 - MCIERR_VDP_INVALID_TIMEFORMAT
      MMPM/2 command does not support the time format.

  5114 - MCIERR_CLIPBOARD_ERROR
      A problem with the clipboard occurred.

  5115 - MCIERR_CANNOT_CONVERT
      Unable to convert clipboard format.

  5116 - MCIERR_CANNOT_REDO
      Cannot redo previous action.

  5117 - MCIERR_CANNOT_UNDO
      Cannot undo previous action.

  5118 - MCIERR_CLIPBOARD_EMPTY
      The clipboard is currently empty.

  5119 - MCIERR_INVALID_WORKPATH
      Work path given is not a valid OS/2 path.

  5120 - MCIERR_INDETERMINATE_LENGTH
      Cannot determine length.

  5121 - MCIERR_DUPLICATE_EA
      An Extended Attribute of this type already exists for another
device.

  5122 - MCIERR_INVALID_CONNECTION
      This connection is not valid.

  5123 - MCIERR_CHANNEL_OFF
      Primary channel has been turned off.

  5124 - MCIERR_CANNOT_CHANGE_CHANNEL
      Can not change this channel.

  5125 - MCIERR_FILE_IO
      Error occurred during file read/write.

  5126 - MCIERR_SYSTEM_FILE
      Could not find VSH data for RTV record.

  5127 - MCIERR_DISPLAY_RESOLUTION
      Display resolution not supported by ActionMedia II adapter.

  5128 - MCIERR_NO_ASYNC_PLAY_ACTIVE
      Currently there is no asynchronous play active.

  5129 - MCIERR_UNSUPP_FORMAT_TAG
      Unsupported format tag.

  5130 - MCIERR_UNSUPP_SAMPLESPERSEC
      Unsupported sampling rate.

  5131 - MCIERR_UNSUPP_BITSPERSAMPLE
      Unsupported bits per sample.

  5132 - MCIERR_UNSUPP_CHANNELS
      Unsupported number of channels.

  5133 - MCIERR_UNSUPP_FORMAT_MODE
      Unsupported format mode.

  5134 - MCIERR_NO_DEVICE_DRIVER
      No device driver found.

  5135 - MCIERR_CODEC_NOT_SUPPORTED
      CODEC can not be found or cannot support the current video mode.


  5136 - MCIERR_TUNER_NO_HW
      The device does not have tuner capability.

  5139 - MCIERR_TUNER_CHANNEL_SKIPPED
      Channel skipped in region.

  5140 - MCIERR_TUNER_CHANNEL_TOO_LOW
      Channel too low for region.

  5141 - MCIERR_TUNER_CHANNEL_TOO_HIGH
      Channel too high for region.

  5143 - MCIERR_TUNER_INVALID_REGION
      The region file either does not exist or is invalid.

  5144 - MCIERR_SIGNAL_INVALID
      No valid signal present.

  5144 - MCIERR_TUNER_MODE
      Frequency was last set directly. Cannot determine region,
channel, or fine tuning.

  5146 - MCIERR_TUNER_REGION_NOT_SET
      No region is defined.

  5147 - MCIERR_TUNER_CHANNEL_NOT_SET
      No channel is defined.  Channel must be set whenever region is
set.

  5149 - MCIERR_UNSUPPORTED_ATTRIBUTE
      Current mixer hardware does not support the attribute.

  5256 - MCIERR_CUSTOM_DRIVER_BASE
      Reserved for future use.