This is the "fix" (thanks to Microsoft support):

In Security Settings/Local Policies/User Rights Assignment make sure the account you want to use as your proxy has these privileges:

Act as part of...

I'm attempting to use the account that runs SQL Server and SQL Agent.

Yes, I even found the typo (comma after 'RalphPwd'). When I execute it with the "Get" option it seems to run, although I don't get any results. I've...

We're running SP2 so the permissions on the "temp" directory were OK (full access). I've tried running Profiler while executing xp_sqlagent_proxy_account and the message I get is: "'xp_sqlagent_proxy_account' was...