For the past three weeks I've been having this issue. If I am in an application on Facebook and try to post something to my feed (i.e. from Mafia Wars), the pop-up is just blank, and I can't post it to my feed. It works fine in any other browser, it's only Safari that doesn't want to work. I am on Mac OS X v. 10.5.8, and Safari version 5.0.1. I've tried removing and reinstalling Safari, Java, & Flash Player. Anyone have any ideas?