Replying to "Javascript false"

I'm getting a blank, white screen that just says "javascript false" when I try to use some buttons on the navigation bar of NS, mostly on the profile stuff. This also happens after replying to threads sometimes, instead of opening back to the forum page.
In addition, I opened an online friends page from the online friends list on the left (not the dropdown one), and the popup opened fine, but the main Firefox page did the javascript false thing.
Wondering if anyone else is having these problems? I'm using Firefox.