Very strange, I tried what you said, and that didn't work.

I tried to update it in safe mode and it worked, I went to about and it was 6.50. However, when I switched back to normal mode it went back to the old version.

Hmm, very interesting.

Edit: Also deleted ackwed.dta and updated, no error message and a new one was created, still old version O_o

-Alex