Wow, well, now I know! I just had the same problem as you and could not figure out for the life of me what was occuring! You would think that WebAssist would make something like this way more obvious or find a fix for this fast, especially since they advertise the program as being easy for a developer to just set up and pass on to their clients! I can just imagine my client being more than frustrated if I had sent this to him and let him fill out all his categories and add products himself! 
I don't think it's possible to see every potential problem that may occur with any product. I was once a factory auto tech and we were always fixing something that was unforeseen. I've found WA products to work very well right out of the box, and they've always helped post haste with quirks, once at 10:21pm on a Sunday.
And PHP is, well, PHP. Trying to remember the humorous quip about it that my engineering friend who was at Google said but I just can't find it in the nooks and crannies... I really should learn the language so I can stop harassing these guys.
Be well...
Btw, WA dudes, my CMS install went great! Used this thread's subject once, too... rad!


