Yup, happened to me too. I think it was a couple of days after I recieved my axim. When I got home, and tried to turn it on, nothing happened. I did a soft reset, tried to do a hard reset...said something about "Are you sure?", couldn't respond yes or no becuase the damn thing was locked. I freaked, and started to despair because I thought I got a lemon and had to send it back...it took me a while to figure I inadvertantly locked the device.
M'eh, we learn from our mistakes.