Hi silverion, i'm the author of Process Tamer, and i'm here to help!
Usually there are 2 kinds of problems people have: one is that they done select the entire license key text, but it sounds like you did that.
The other one is that on the free license key download page, some people don't notice that there are a series of links for downloading keys, and each link is for a different program -- so it's easy to generate a license key for the wrong app. you might try that and see if that's the problem.
If that doesn't solve the problem for you, email me (firstname.lastname@example.org) and i'll help some more.