I created a drum track on one computer and backed up the project and then put it on my studio computer. Everything is there, the other tracks sound fine, but there are missing beats in the drums. Open the piano roll and it's all there, but it just skips over certain beats.
 
Any idea why it would do that?
 
Both machines are running the latest updates of Platinum.

Have you tried increasing your "Prepare Using" MIDI buffers?. Preferences | MIDI | Playback and Recording,  Mine is set to 1024p

Is it possible that those notes not sounding are not mapped to the correct drum (correct pitch)??   

It looks like bumping up the "prepare using" buffers did the trick. Works like a champ now. Thanks!

Kewell