You never said if you followed *all* the troubleshooting steps listed in the doc reference Torsten pointed you to.
Normally you need membership in the SMS Admins group (seems to me there used to be one on both the site server and a remote site database server, but it has been a long time since I set up a remote SQL Server - if so, you need membership in both) - and the DCOM rights as specified in the doc link.
Wally Mead