Prologue is a VST3 plug-in.  It keeps crashing Sonar everytime I try to instantiate it.  I am using X3d 64 bit.

I don't think it's available as a product separate from Cubase, and is keyed to Cubase.

Hmmm.  That might explain the crashes... It came with the Yamaha MX61 I bought some months ago, along with Cubase AI 6 and Yamaha YC-3B.  Prologue does work within Cubase, but I am not really interested in using it.  I've been a long time Sonar user.  Btw, YC-3B is also a VST3 plug in and it works just fine in Sonar.
 
Thanks for the reply.

AlKal
Hmmm.  That might explain the crashes... It came with the Yamaha MX61 I bought some months ago, along with Cubase AI 6 and Yamaha YC-3B.  Prologue does work within Cubase, but I am not really interested in using it.  I've been a long time Sonar user.  Btw, YC-3B is also a VST3 plug in and it works just fine in Sonar.

Correct. The YC-3B is not keyed to Cubase. Same situation with Sonar and many other DAWs - some plug-ins work in other programs, some don't.

True. In fact I ran into this with some Cakewalk plugings:  I recently needed to re-install X3. Before re-installing I opened X2 and the plugins that came with X3 showed up there but would say something like “This is authorized to work with Sonar X3 Producer”.  After re-installing X3, I checked again. Now, most are also working in X2, but some like the pro channel Tape emulation do not.