Sorry but I don't know anything about apc, however a quick check on their web site prompt a few questions, of which the answer may already be yes...
To quote the manual...
"On Windows, APC needs a temp path to exist, and be writable by the web server. It checks TMP, TEMP, USERPROFILE environment variables in that order and finally tries the WINDOWS directory if none of those are set."
have you set apc.write_lock to true?