Oh.  And if I get a file open that has many tracks and or plug ins, I get lots of audio drop outs.  Shouldn't be happening based on the specs of my machine, and based on this being a sudden and new development.

If this is "sudden" have you tried to do a system restore to a day when you last knew it worked? That exception code is most often thrown by Windows over a driver error. Is that giving you a blue screen or just crashing SONAR?
 
Another place to check is Windows Event Viewer and look for more detail on each of these (Windows should have them all logged).