JonD

If you have an onboard sound card, install the free ASIO4all driver and see if that combo works. If it does, then you've isolated the Soundblaster as the problem. If the above doesn't help, then the next step is do a clean uninstall/reinstall of Sonar. This includes deleting registry entries, so you need to be careful or let someone who's more tech savvy do it for you (Do a search to find the step-by-step instructions. They've been posted in the old Sonar forums many times).

If you didn't already, make sure to do a RESET of your VSTs before you RESCAN. I noticed that many users forget the reset part and just do the rescan (which won't help in fixing any initialization errors).

I think it's likely. IIRC he posted a few times at the old CW forums as a Sonar user...