Cannot Forward or Reply to Emails

No, but many email problems can be fixed by deleting the account and recreating it. Try that.

it' happening to me too

Good idea. That works for me. Remember to back up your emails before you delete the account though.

Always good advice. I would add that I would not use the iPhone as the main repository of ANYTHING. Nothing against the iPhone itself, but it is very small and very losable. 🙂 The central repository of all your mail, contacts, and calendar should be either your desktop PC or an online service, like Google or MobileMe. The iPhone should just provide access. In the event the iPhone is stolen, lost, or spontaneously combusts, you will be ok. (well, not if it combusts in your pocket, but that is another story.... 🙂 )

We found at another forum site that you have to turn off WiFi to forward or reply to email. We tried it, and it worked. We then verified this at the apple support site trouble shooter, at this page http://www.apple.com/support/iphone/assistant/sendmail/#section_4

Also, we found that if you "forget" the wifi account, and then set it up again, that now we can reply and forward using the wifi account.