I've reported the issue on Broomstick Bass forum (KVR), but just in case if someone here has a solution:
 
Broomstick Bass works well on SONAR 8.5 Producer, but it crashes newly installed SONAR X3e build 244 every time when I try to insert it into a session (new or existing).

I've tried changing the plugin settings in Sonar's VST Manager, but without success.
OS: Win7 32-bit, fresh installation

Any suggestions?

After upgrade to X3 did you perform the VST reset and rescan http://www.cakewalk.com/Support/Knowledge-Base/2007013315/SONAR-X3-Full-VST-Rescan-Recommended-for-Upgraders? If that does not fix the issue, try running X3 as administrator.

Scook, thanks for the quick reply, it's appreciated!
 
Rescanning as suggested (with the reset) did not help.
 
"Run as Administrator", however, did work - the plugin loads and it works.
 
Thanks a lot!

Glad it worked for you.
Consider editing the subject of the initial post adding [Solved] to it. This helps others looking for solutions.
 
Also may want to update your KVR post. Usually the administrator requirement is because the plug-in has not been updated to the Vista (or newer) security model.