Here's one of those little MIDI gotcha's that every beginner eventually runs in to:

"I am loading standard MIDI files into my sequencer for playback. They seem to work fine until I need to transpose something. When I transpose the sequence the drums play erroneously. What gives?"

At this point I'm sure many inSync readers are saying, "Ahh yes, I remember when I first ran into this." The problem is that when you transposed all of your MIDI tracks you changed the note values of them: an E might become a D and so on. Of course, this is what you want. However, on your drum track you need to be aware that each note corresponds to a different drum sound. The E might be a snare, while a D might be a crash cymbal. Transposing a drum track will effectively change all of these instrument assignments by causing different notes to be played from the sequencer.

You need to either (1) Transpose all the tracks except the drums, or (2) transpose all the tracks and then re-transpose only the drums back the other direction by the same amount. For just this reason many software-based sequencers allow you to set a drum channel or track that does not transpose when all of the other tracks do.