With release of v5, the registration code was revised. You may be trying to use your old v4 code with v5. I recently received a registration code from you but it does not work on my version. You cannot use a v5 reg code with v4.
Nothing seems to work.
If this is not the case, the code is corrupt and will not work. I received the registration package, installed NYC , but it won't accept my registration code. There are instructions for use of the registration code on your sales receipt. Here they are again. Then press the Reg.