Don't get yourself bogged down here, but if the zencart team hadn't already rectified this, the "correct" fix (vs your fix) can be found here:
http://stackoverflow.com/questions/8...-fix-available
I'm not suggesting that you re-fix by following the example given because, well, it isn't really a problem for you to fix. It is/was something that the zencart team needed to take care of. For your part all you need do is ensure that you didn't miss anything with you upgrade (as it appears is the case)
Cheers
RodG