I'm working with MIDI drum tracks in X1.  Everything sounds fine during playback, all notes are triggered in the drum plug-in.  When I export the entire project, the snare drum is not audible in certain spots.  I've never had this problem before.  Any suggestions would be appreciated.

Could be too small a value for "Prepare Using nnn Millisecond Buffers" in Preferences > MIDI > Playback and Recording. If the value is at the default 250, try 500 or more. Could be that synth does not want to export using "Fast Bounce".
 
It might be easiest to freeze the track before exporting.

Agree it sounds like a buffer problem.  I used to have this exact problem a lot.  No more since changing buffer size.