The only time I saw this was years ago, I had bad parallel port. Unfortunately this means a new MB.
You might try your dongle on another system. If it happens again, perhaps the dongle is bad.
If you suspect it might be your port, you can always try making another system a license server.
One other thing to try. The license server needs a running network adapter to function properly. Even if the system is offline. Some adapters shut down if they are not being used. The solution was to load the software adapter off the Windows CD. Just go to control panel networking and add a new adapter. Then select the software adapter from the CD (Make up any IP address when asked). You don't have to remove your real adapter. The software one is only used if nothing else is avaiable.
Sorry I can't help more,
Urp