Well I looked into the vB forums about it, it's a common problem. Just google "quick reply hangs vB"
Couple links that held solutions from what I gather. Of course I don't use vB, so the solutions are just jargon to me.
http://www.vbseo.com/f77/quick-reply...y-404-a-19819/
http://www.vbulletin.com/forum/archi.../t-238983.html
I'm not posting either links as definite fixes. This post intends to serve as confirmation to admins and users its' not their browsers. It's vB. So no need to fiddle with your default settings if the quick reply bug is unsettling you. It isn't you.