bbPress.org

By the way, even when we fix the plugin problem, your setup could benefit greatly from a PHP opcode cache (eaccelerator, xcache, APC, etc.) We just have to find one that’s compatible with Windows and IIS which will take some research. It should cut your page times in half, on both bbPress and WordPress.

Here’s one possibility:

http://www.sitebuddy.com/PHP/Accelerators/eAccelerator

That site has pre-built windows binaries for eAccelerator as well as good install directions.