Quote Originally Posted by mvstudio View Post
It seems that's the actual issue. The strictness of mysql which I have not even the most remote idea why is there, is the root of the problem.

The patch that Cindy provided didn't work, but the version of the patch that carlwhat provided did work in the end at least for now. I'm hoping my hosting provider won't complain about it! =D
Suggest following the "rabbit trail" at the following github issue which led to a code change incorporated into ZC 1.5.7 that is compatible with ZC 1.5.6:
https://github.com/zencart/zencart/issues/2426