I have a client who uses AutoCAD Civil 3D 2009. For some reason, and this only affects this user on this PC, he has to attempt to start the application multiple times as it has problems connecting to AutoCAD's network license manager (see attached PNG file). The client eventually connects and is able to use the application, usually after 6 or 7 attempts.
When I first began troubleshooting this issue, I found this article on the Autodesk support site which specifically addressed the error the client gets:
Unfortunately, increasing the setting specified in the article has not resolved the issue, even though I have increased it multiple times.
Searching for an answer online has been difficult as it seems that not many people who get this error have found a resolution that works.