Java Script Error

Please help,

I’m getting this error below in a box under my Pricing page for each
category. I don’t know how to get rid of it. I don’t have any inventory, nor will I have any in the future.

Inventory tracking will not work because your site has javascript errors.
Possible solutions

Please goto my website http://www.realestateshotz.com

Under the Pricing tab.
Thank you,
Frank

http://ww.wp.xz.cn/extend/plugins/simple-e-commerce-shopping-cart/