Problems adding to cart in custom front end

Ver: 1.3.9b

My client wants a fully custom front end for her store which I've done but....and there's always a but.....I am having trouble getting the selected product into the shopping cart. I found this code fragment (which claimed to do the job):

but the closest it comes is to take me to the page that lets me put a product in the cart (the product ID comes across properly but the quantity doesn't) and I still have to click to add the product to the cart. Oh, and on IE it doesn't even do that - just wanders about in the ether for a few minutes and comes back to where the original page.

Any help would be appreciated as the client is really feeling the pressure from her client.

Thanks,

Mike

Zen Cart is not designed to be used the way you're proposing. It can be done, but it takes a great deal of knowledge and work.

I did the same thing for a store using OS commerce and it wasn't anywhere near as difficult as this is turning out to be.

Maybe someone's got an answer, or at least a direction to point me in.

Thanks,

Mike