Kaelten, I just got the white page trying to get a post preview from the newreply page. Maybe 5-10 minutes ago. Of course I'm a moron and didn't follow my own previous advice and had to retype everything.
Edit: I tried to a bunch of things to get the error again and couldn't.
Blizzard's forums don't remember what you typed on a back. Neither do any vB forum I've ever run or moderated, to the best of my memory. It's possible the most basic text field might, I think the JS they use on the field screws it up otherwise. I got into the habit of copy and pasting my posts before posting a loooong time ago :/.
If tabindex is 1 on everything, it should go in order encountered in the HTML I think. Are the elements out of order?