You might have a better chance of getting a good answer in the Administration forum.
Did you ever find a solution to this problem? I am having the same exact issue with a 2012 installation.
Here is the text of a response in the Administration forum. Thanks to Jeremiah Griffiths:
I had this issue as well, it turned out to be a windows security issue. Try disabling the User Access Control, restart, and then change your License Server.
Something about the UAC was blocking the changes when I did this, as soon as I disabled UAC it worked fine.
If you run into any other issues, you might try running the license manager with a Run As Administrator setup and see if that makes a difference as well (I can't remember if I had to do that as well).
Trying giving the IP address of Server instead of The Server Name.
Say For Example firstname.lastname@example.org
Hope this will help you...
We had exactlyt the same problem and were able to solve it by running the license manager in Administrator mode. Right click on the shortcut and "Run as Administrator". You may have to actually get an Administrator if you aren't allowed to do this on your own!