It sounds like a passive adapter. These do not work with the PS/2 version of the KeyWiz. Those "adapters" are specifically for dual-interface devices, like certain USB / PS/2 mice.
With the PS/2 KeyWiz (different from the KeyWiz USB MAX) you would need to use an active USB keyboard converter. While any of them will provide limited functionality, only the ones which are intended for gaming will provide proper functionality. However, even with these, you would not be able to program the unit as the adapter would act like a firewall between the software and the interface. These special adapters are also usually quite costly, so it would likely make more sense to upgrade to the KeyWiz USB MAX for native USB support, true EEPROM keyset storage, user-defined debounce rates, more inputs, etc...