Hi all,
right after I posted this message, I found intrf.bbw. Unfortunately, deleting it didn't solve the problem. After restarting my computer I tried to run bbw.exe as an administrator. Again, no luck.
I did find a file called PluginScanLog.log. If opened in Notepad it reads:
Plugin Scan Log
Calling Windows FFilterMapper2.EnumMatchingFilters...
... Windows FFilterMapper2.EnumMatchingFilters succeeded
Counting candidate plugins in the Enum...
Any ideas?