From the Roland site: The sound module section of the MV-30 is not GM compatible so Standard MIDI Files may not play back properly. However, Standard MIDI Files in format 0 or 1 can still be loaded into the sequencer section of the MV-30 with the following limitations:

1. Format 0 SMFs will be loaded into track 9.

2. Format 1 SMFs will be loaded into tracks 9-16.

Note: If more than 8 tracks are present in format 1 SMFs, the additional tracks will be merged into track 16.

I know this doesn't address your problem but at least you can tell what the mv-30 is doing with the files