A recent blog entry from the Dynamics GP Support and Services blog hilighted the RM Transaction Unapply tool in the PSTL. It also included instructions on how to install the PSTL itself
The complete blog entry is here if you're not a DD member.
I've copied the section that details how to install PSTL below so that we'll have it if we need it (I really hate having to search for stuff like this)
This will help with the error:
Incorrect registration code!, please verify registration code