Unencoded ampersand in WordPress causing me validation errors

Hi,

When I enter submit search terms into the search bar on my site (http://www.projectdisobey.com/disobeyclothing/), and then put the resulting page through a validation test at http://validator.w3.org/check, I get the following validation errors:

(See attachment)

I know that all these errors are resulting from an unencoded ampersand. My question is, which WordPress file do I need to go into in order to change the ‘&’ to a ‘&’?

Can anybody help me?

Thanks

My best guess would be to look in the themes/eCommerce3 folder for the function.

If the theme isn’t free, do they provide support?