This is the error I get while running the migration assistant on my Windows 5.5 vCenter server. VMware update manager is working correctly so my guess is that the database is available and working.
Error messages: Error: Unable to connect to VMware Update Manager Database, Cannot proceed with migration
Resolution: Please check that VMware Update Manager Database is reachable before migration and Please make sure Migration Assistant is launched under service account for VMware Update Manager
My guess is that my current account does not have enough permissions to access the database. I'm currently running the migration assistant with my admin account which is a domain admin account with administrator rights locally on the machine.