Unfortunately this was a bug with wyUpdate when it self updated. Tell him to click cancel / quit. After wyUpdate has closed, tell him to open a cmd window (Click Start, type "cmd", press enter). Then have him paste in the following lines:
rmdir /s /q "%userprofile%\wc"rmdir /s /q "%appdata%\wyUpdate AU"
Then have him press the Enter key on his keyboard. This will delete the update cache folder (thus solving this unfortunate wyupdate bug).
After that he can re-run the update and it will succeed. I truly apologize for this problem. We should've caught it in our tests. We're making sure nothing like this happens again.