If you were provided with a Registration Coupon so that you could
acquire your license from the MachSupport.com web site, then you
can just issue a new license yourself by providing the PCID to the
license server.
If BuildYourOwnCNC provided the license file to you, then you will
have to go back to them for corrective action.
In any case, their Mach3 USB Interface Board should not be expected
to run under Mach4.