Sounds like this info might be a little late for you, but I just had the same issue and cleared it up by going to options and turning off the full keyboard view in Portrait view keyboard setting.
Thanks this info helped alot! I went to the store and they switched out my blackberry storm twice because the dial pad stopped working. Everytime I came home and but my back up file on the phone it would do it again. So pretty much techs at the store and on the phone couldn't solve this problem. So I Googled it! You go to options, screen/keyboard, portrait view keyboard select suretype. And it fixes the problem! yay for forums!