Have you double checked that any of the processes are not running?
I Checked for the processes but none were running. I bounced the App server , stopped the services and then installion was complete
Common problem in Windows, regardless of the application. The operating system will not release DLL’s correctly all the time. The console overwrites some DLL’s in use by the appserver, so they have to be released by the OS. Sorry, but this is a common M$ issue.