You can use floating TestExecute licenses on a License Manager... that is, how it's designed. The problem is that it sounds like your TestExecute installations are not finding the licenses on the License manager. They are looking to run as node-locked licenses.
The problem occurs whilst trying to active the floating licence in Licence Manger, not whilst starting Testexecute. The Licence Manger is installed in a VM.
Then what it sounds like is that the License Manager on a VM is not set up properly. A best practice is that the License Manager should be a physical machine or on a VM that is configured to run on a static piece of hardware.
I think you're best bet would be to contact support directly. I think they may need to help you with the License Manager installation to make sure it is properly configured to run on a VM.
