ok, I took a look at the tar file you said and it doesn't contain the evaluation packages, so maybe you downloaded it from the CVS?
Anyway, you can specify the branch when checking out the code from CVS like this:
cvs -z3 -d :pserver:mailto:anonymous@cvs.openacs.org:/cvsroot co -r oacs-5-2 evaluation evaluation-portlet dotlrn-evaluation
Regards,
jopez