error 11 indicates the following:
"Device Does Not Exist: The specified device for login or logout does not exist in the system."
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_programming_usage_guide_chapter09186a00802e28fc.html
the user device template should match the actual device, but with 7940 and 7960 it should work fine. Make sure that the user is accocited with EM profile, that the service is running, and that the user ID that you are typing in is the actual user ID not a profile name.
Chris