My girlfriend claims that her 7130e keyboard locks and all she can do is call people who are in her history. The first time she told me this I figured she had a bad phone, but this is a new one and its still happening.

Its SUPER common for her to hit two buttons at once as the phone is still new to her and she isnt used to the keyboard yet. She claims that when it happens there is nothing that she can do, but that sometimes the keyboard just starts working again.

Any ideas what it could be? and how to unlock it when it happens? (other than removing the battery, which DOES fix it)

if there is no password set, click on the * and the send key together, or double click on the wheel. The lock is enabled when you keep the * key pressed. You can enable dialing with the keyboard locked