OK - have you tried trashing the Photoshop Preferences file? This often fixes all sorts of weird behaviour in PS. Here's some info:
Photoshop Tips: Trashing the Preferences File | CreativePro.com
I doubt very much that it's a bug in the program if you are using a legitimate version of CS3 (i.e. not a pirated/cracked copy), otherwise this behaviour would have been noted by many other users (and hopefully fixed by Adobe by now). What are the plugins that are giving you the problem?