I use the script all the time. As the previous poster mentioned, you have to move the track you're splitting to the bottom of the project.
Clone the original track if you want to save it, the source track is destroyed by the script
Move the cloned track you want to split to the end of the project.
Select it and Process->Run CAL->Split Notes To Tracks
Set the source track to the one you want to split
First destination track to the next track number (empty track)
Destination channel (10 for drums)
Destination port (the midi device you want the new tracks to point to)
Once you run the script, it will create a new track for each midi note and leave the original source track empty (no data).
A couple artifacts, some of the new tracks will be 2 or 3 times longer than the original, select all the new tracks and do a Bounce To Clips to make them a reasonable length again. After bouncing to clips save the project and exit Sonar.
Split Notes To Tracks appears to introduce some instability, even across incarnations, I usually get exactly one crash when I hit play on a project after using it. You might want to hit Ctrl+S before hitting play.