The offered Release Candidate can not cope with GnuPG 1.4. - just 1.2.x
if available please exchange the release candidate on sourceforge! It is dangerous to distribute such a old GnuPG version with WinPT (1.2.2 iirc).
If you don't have a fix for this please *state* the fact that it is not compatible with the 1.4-branch and compile the release candidate with the newest compatible GnuPG-Version (1.2.9 iirc).