Hello,
"Queued" state means Baclup Exec is not able to find the target.
1 : Go to the Devices TAB-->Right Click on the Server name and click on "Paused", right click again and click on "Unpause"
If did not work:
1 : Turn OFF the server and the library
2 : Turn ON the library first, let it boot
3 : Turn ON the server and check for the Device Manager for the Library.
Hope this helps....