Cannot connect to license server

We updated to SolidWorks 2013, and moved our license server to a new location. New installations of 2013 are working just fine, they can see the server and get the license. Systems that were using 2011 and have been updated to 2013 cannot access the license server. Short of reimaging those systems, is there anything I can try to get them to see the license server?

The systems in question ping the server just fine, and I can see no visible differences in the new systems versus the ones that were updated. Firewall settings are the same (managed in GP). I can find no port conflicts. Systems are all Windows 7x64 Enterprise, all are running SW 2013 Premium x64 SP1.0.

SolidworksAdministration