We've been having this problem too.
After searching the archives and following Gavin's suggestion to update Hardcopy.pm yesterday (replacing 1.94.2.2.2.1 with 1.94.2.2.2.3) we still had the problem. After I read the rest of the thread this morning and restarted Apache, the problem seems to have gone away.
So thanks Gavin, both for making the initial suggestion and for giving a kick to those of us who need to be reminded to do the obvious!
Hal