cvs uses an internal version of the 'RCS' commands in all modern
releases. However, many folks used 'rlog' and friends in their
commitinfo and loginfo scripts. You may wish to do something like:
cvs checkout CVSROOT
cd CVSROOT
grep rlog *
to try to find the culprit.
Given the error above, you will wish to pay special attention to
how your implementation of the CVSROOT/loginfo process works.
A reasonable replacement to using 'rlog' may be to use 'cvs -n log'
on the file in the local directory rather than on the full pathname
to the CVS repository + module pathname + filename.
Enjoy!
-- Mark