You can also check a little log file in /tmp/mstatus-ver (or something similar) and see if it uses the right key. Another thing, remember that the key (Dekstop / Web Key) must be inserted without any trailing characters. Regards.
verify(http://api.ping.fm/v1/user.validate,764b6a4fb9a5d1a8c1afb8a8f45a1295-1265903274); out is FAIL
m= status m= status m= status m= status m= status