I think I figured this out. I installed a plug-in (Blatner Tools) meant for CS 5. Once I removed the plug-in files the program allowed the changes to preferences without crashing. Apparently there is an updated version of Blatner Tools. Had to find that out the hard way.
This suggests you're not running the latest version of CS5.5, 7.5.2. If you are, it should prevent you from installing incompatible plugins. But a bug in the original 7.5.0 release of CS5.5 mistakenly allowed incompatible plugins to run.