Resolution:
If you copy a Process Engine or iProcess Engine (pre 10.2) release to a new machine and re-license although the license will appear to work it will be invalid. This is because of the change of machine name between the two machines.
To fix this, remove staff.dat
If pre-10.2 request a new license and then re-license again
or 10.2 and over create a new license with swconfig.

In either case you will need to re-start the engine at that point to read the new license file.