Using the version of your cart available today from the trial download, I seem to be experiencing a bug when I add a required variant type of text box. To recreate the problem, add a variant of type textbox to a product with a variant name containing a space, and make it required. In my case, I'm evaluating your product for use as an event registration tool, and I needed to include a required textbox field for "Badge Name" (among others that would include a space).
The error indicates that you are trying to use the variant name as the control name for a layout table and the required field validator, which will not work if it contains a space. I could simply include an underscore or something similar, but that certainly doesn't look professional to the end-user.
Hopefully, this is something that can get patched or worked out quickly, because it would seem to be a show stopper for many. I'm trying to find a cart that would allow me to ditch catalook once and for all, mainly because there is little to no support for even the simplest of questions or problems and because it is incompatible with an average end-user admin. Your product seems to work nicely, so I'm doing someting wrong in creating these variants, please let me know.