Shopping cart

[eluser]1cookie[/eluser]
hi

I'm trying to get a script from the net working, but am not having much luck with it. Ive attached my files. Upon clicking any one of the 'Add' submit buttons, the script won't update the cart? I've checked the console error log and get the following error: see
screen shot for a description. From the console, the path in the error doesn't seem to make sense? I mean, I'm looking for a path along the lines of:

Code:

http://localhost/demo/demo/

Any ideas?