404 Error after mod made

Please help!!!!

I made a modification to my template: catalog/view/theme/default/template/product/product.tpl I was trying to add the facebook "like" button using instructions from a post I found on the forums. My site was working great before making the mod, but immediately after altering the code, I was able to get to my homepage, but any time I tried to navigate my site, I was sent to the 404 error: file not found page.

Any ideas? http://www.thetutuplace.com

TIA.

*UPDATE*: I removed the SEO keywords on each of the categories, and all links work now.