That happened to me on my old computer using UOKR. Nothing worked to fix it. Nothing. I was in contact with in game GMs, online tech support, everything. (thats the only time i have seen an in game GM since playing again).
I reinstalled, deleted the desktop folder, deleted this, that, etc. Nothing worked- except changing to 2d client.
It was strange, it was only on my Siege character that the game crashed. I even got a trial account to try it, and it worked fine... only my main account Siege Perilous character crashed...
So... if you have the same problem as me- good luck... you are screwed. But if its a diff problem, good luck, you may get help
