Hello,
Go to the Devices TAB-->Right Click on the Server name and click on Paused....Wait for 2 to 5 seconds and unpause it again...If this dont work:
1 : Turn OFF the Server and the Library and disconnect the Library
2 : Turn ON the Server (This will delete all the entries for the Library from the OS)
3 : Turn OFF the Server and connect the Library
4 : Turn ON the Library first and let it come up
5 : Turn ON the server and check the Device Manager for the Drives and the Medium Changer.
Make sure that you are using Symantec Drivers for the Drives and Medium changer : Unonown (Microsoft Drivers)
Hope this helps...