Receiving 404 Error when I have my SEO URL mod on

I am trying to find out why I am receiving this 404 Error when my SEO is turned in my shop: How can I resolve this error?

The webpage cannot be found

HTTP 404
Most likely causes:

• There might be a typing error in the address.
• If you clicked on a link, it may be out of date.What you can try:

**Retype the address. **

Go back to the previous page.

**Go to and look for the information you want. **

More information

This error (HTTP 404 Not Found) means that Internet Explorer was able to connect to the website, but the page you wanted was not found. It's possible that the webpage is temporarily unavailable. Alternatively, the website might have changed or removed the webpage.
For more information about HTTP errors, see Help.

... And you are using which SEO mod?

Kim:

... And you are using which SEO mod?
Ultimate seo it seems. The problem seems to be resolved tho.

My hosting company, stated the problem was on there end, and corrected the problem.