After applying the post SP2 MCMS2002 hot fix the "Database Configuration Application" produced the following error. "Unable to query the condition of the selected database. The selected database may be corrupt. Please select either an existing MCMS database or an empty database. Automation error -2147221101"
The solution to this problem was to overwrite the local "_dca.ini" (found in "C:\Program Files\Microsoft Content Management Server\Server\Setup Files\SQL Install") file with the copy on the server containing the MCMS Database and MCMS installation.
This article (http://support.microsoft.com/?kbid=913401) basically contains the solution I used but it describes the solution for a different error message.