I was trying to remap the RUN function key, ALT+T ( in my case, ALT+W as I remapped W as forward movement) and when I opened the options, selected RUN, and then when the box says to hit the key to remap to, I hit CAPS, and the game crashed. I tried this several times, with the same result.
On a side note, I had to wait for the server each time I did this. At first I thought the GM was resetting the server, but after the server being down EVERY time I did that remap, I guessed it was a glitch in my client.