The serial I'm using was fine up to and including until 2.41 but stopped working with 2.42b. If I remember I used a keygen program to generate it. Looks like the format has changed with 2.42b because I'm unable to generate a working key. I quite understand that you would not want to share a key you paid for, I'd do the same thing if I was in the same situation.

Cheers, Ian