Some commands of PM123's playback engine return one of the following result codes:
| Return code | Description |
|---|---|
| 0 | No error, everything is fine. |
| 1 | The command is not processed because an earlier command in the current set of linked commands has failed. |
| 2 | One of the commands arguments is bad. |
| 3 | The command requires a current song. |
| 4 | The command is only valid for enumerable objects like playlists. |
| 5 | The navigation tried to move beyond the limits of the current playlist. |
| 6 | The command is only allowed while playing. |
| 7 | The output plug-in returned an error. |
| 8 | The decoder plug-in returned an error. |
| 9 | Cannot load or play invalid object. |
| 10 | Invalid PM123 location string |
| -1 | General error. |