Magento

We have several stores that are set up using Magento and we customized it with the help of a contractor.  The contractor created one theme and then we have created other themes using the same code.  On the site that was delivered (http://www.vinylbedding.com), the side navigation works fine, but when we copy the theme over and try using it on our other sites: such as http://www.justwalkers.com, the default side navigation bar gives a 404 error, but it is only from the home page.  For example if you look at http://www.justwalkers.com and click on any of the manufacturers (http://justwalkers.com/walkersandrollators?all_manufacturer=205), it will give you the 404 error.

I know that this looks funny because it has the extra walkersandrollators in there, but that is just an extra folder that our contractor said was necessary for the top navigation to work correctly.  You can see that it also exists in vinylbedding (http://vinylbedding.com/vinylbedding?vb_type=338), but it works.

Any ideas.  I feel like it must just be some small setting that I am not hitting in the admin panel because the code is the same on both sites.  I even copied the code and the products over to http://www.bracesandsplints.com and it doesn’t work there either.

Thanks for any help.