Symantec BE 12 and Dell Powervault TL2000

We have just moved a server from physical (Windows Server 2003) into VM.
This is the server where Symantec is installed.
Before this the back up jobs worked well.

After we did this the back up tapes are not reachable.
The scheduled backup jobs all report "The operation failed to aquire the minimum number of drives and media needed". When I put the tape device online it goes back to offline after restart.

When logging into the web admin for Powervault there are no errors reported.

In computer Management I can see the IBM units under Libraries, but they all have red dot with the white cross above. 

Are there any issues with moving the backup server to VM?
Are there any extra stepts to take in order to get it back to working?

Thanks for all ideas