If you’re trying to install McAfee EPO (ePolicy Orchestrator) 4.0 and setup is failing when it tries to connect to your SQL Server with a variety of worthless errors, be sure that the server name you specify matches the result of this SQL query exactly: "SELECT ServerProperty(‘ServerName’)". After hours of messing around, a network trace revealed that this was query the last thing setup issued before it failed. In general the query seems to return the SQL server’s shortname, so, if you’ve done something smart like I did and provided the FQDN of your SQL Server to setup, setup will fail and tell you it can’t connect or the port number is wrong or something else in that general vicinity.
Another thing I learned from my network trace – make sure the credentials you provide setup have sufficient SQL access to create AND drop databases. Setup tests its ability to do so by creating a database with a GUID for a name and then dropping it.