It sounds as though you might be simply adding the most recent license
EXTENSION. You need to first add the original license - the one that has
NeoPack as part of the filename - then add the most recent extension
There is also another way if you still have access to the old server.
Copy this file
C:\Program Files (x86)\Timestone Software\License Server\tslServer.lct
from the old computer and put it in the same place on the new.