i bought it on steam and do i have to play the regular game to update it?
Steam likes to autoupdate everything for whatever reason it has. The current version of Warband (1.150) is incompatible with cRPG right now (uses 1.143). The workaround should bypass the forced update, and allow you to play cRPG normally.
If that doesn't work for you, can you tell us if it gives you the same error with the Native module?