Ok, just to wrap this up - I uninstalled Aperture 3.2.4 as well as every trace of the Topaz plug-ins I could find. I then reinstalled Aperture 3.3.1, updated the Aperture library as required by Aperture 3.3.1, and then redownloaded and reinstalled Topaz Fusion Express and Topaz B&W Effects. The problem remained the same as before. I rebooted the Mac and lo and behold the Fusion Express and B&W Effects combo now worked. So I redownloaded and reinstalled Lens Effects. The problem reappeared with Lens Effects. Again I rebooted and the problem went away. I have no clue why my configuration required the reboots after installs - there is nothing I can find with regard to any of the apps that says a reboot is necessary to make things work (and of course I never had to do that before Aperture 3.3). However I am happy that everything is now working.