Microsoft acknowledge that this is a bug from SP3 but is not corrected in SP4 or SP5.

This message appears in the error logs - but when it does appear, if you don't already have a connection open - it's impossible to get a new connection. If the connections are erroneous or SQL Server based (ie. a process trying failed and is trying to log in) it's hard to tell where they are coming from without rebooting SQL Server and kicking all users off.

The work around is to set up an alert in the Performance Monitor and get it to put an error message in the log when the number of user connections starts to rise.

A trap for young players.