Problem:

After installing licenses into a License Server located on a Virtual Machine, the licenses fail to work after the virtual machine has been rebooted. The following error is reported.

'Warning! The license file appears not to belong to this server.'

Resolution:

The License Server is not supported on virtual machines, and has to be installed on a physical machine.

Installing the License Server (as used for Net Express, MFE, etc) is not supported on Virtual Machines. 

The License Server is locked to the machine using a specific set of hardware properties and ids.  This finger print will change each time a machine is booted and there is no way to configure the VM images to stop this.