>The above error message has cost me the best part of a day, with no end in sight. I am trying to develop and test a setup program which is to install the SQL Server Desktop Engine under most circumstances, and then create a new database and load up some tables. The SQL Server Desktop Engine has no user interface in which to specify type of user authorization. The server and client are the same machine, which makes the error message mean essentially "I can't talk to myself because I don't trust myself!!!". Aaaarrrggghhh! Granted, it might be because I happen to have other SQL Server connections from my machine, but I can't ship software that breaks because the user happens to have other SQL Server client stuff around. Is the SQL Server Desktop Engine a useless piece of trash, or am I missing something easy here?

I think your PC cought paranoia virus <g>. Sorry couldn't resist.