When launching, Toad gives the error "Minimum driver version requirement not met. You will still be able to connect, however some features may not be available".
Whether clicking Cancel or Continue, the message stays up and Toad hangs.
Invalid connection set up as auto-connect exists.
Go to the application data directory, C:\Documents and Settings\Administrator\Local Settings\Application Data\Quest Software\Toad for Data Analysts 2.1 and rename/remove the connection.xml file.
Go into that file and edit it manually, so that the <autoconnect>... </autoconnect> line is set to FALSE for the problematic connection.