I just noticed that the "post" and "preview" buttons don't work with trying to post and entry on the EAA forum. I tried to do a test post on VansAirForce.com, which uses the same vBulletin software and was able to post an entry from my iPad.

There is a fix for this issue on the vBulletin website. You'll need to create an account on the vBulletin forum to see the article and the fix:

http://tracker.vbulletin.com/browse/VBIV-12092