Hello,
I beleive this may be the result of a stale entry in the VSC config file. You can check the file "C:\Program Files\NetApp\Virtual Storage Console\etc\vsc\vsc.xml" and see if there are any controller entries which are no longer valid. If there are, make a copy/backup of the file, stop the VSC service, remove the entries, then restart VSC. You may need to log out and back in to vCenter to see any changes.
Hope that helps.
Andrew