Hmm...that is very disappointing, especially given you only find this information out after purchasing the tool.
In fact, version 1.9.5 RC1 (which we are on) and the copyright removal tool are listed right next to each other on the downloads page...
http://yetanotherforum.net/download.aspx
:-(
1.9.5 RC1 is a beta release and was never intended for a production server. That feature was introduced in the next public release version, which was 1.9.5.5 --
Because you purchased the key, there are two options - upgrade YAF, or modify the source code for the version you have and re-compile it if staying on 1.9.5 RC1 is an issue. 1.9.5.5 runs on .NET 3.5, but 1.9.6.x and above require .NET 4 -- there have been signifigant improvements in the code and performance in newer versions, which is why recommended to upgrade (which is an inline process and generally simple if you follow the rule of 'backup, backup, backup' - no matter what you do - backups help (whether it's YAF or another .NET application).
If you can't find it using the forum search, try my signature link -- searches this site using Google:
Google is my Friend