Help! 500 error, but only in one category

I've checked the FAQ but haven't found this anywhere.

I'm getting a 500 error, but only when I try to navigate to a specific category on my site, or one of the subcategories or products therein. The error is intermittent - I seem to get it one time in three or so.

I talked to my host support, and they said the error hasn't registered on the log, so it's probably a scripting error.

It may have something to do with Ultimate SEO. I installed the module, but it didn't work so I uninstalled it. I think that's when I started getting the 500 error. I then reinstalled it with a patch I found here. It works generally, but that subcategory still gives the intermittent 500 error.

My site is here. The category that gives the error is Alternative Energy- Wind & Solar, and it happens especially frequently in the Sealed Lead-Acid Battery sub-category.

Can anyone help?

Can try clearing your browser cache and/or your router cache if accessing from behind a router

Also in my experience every SEO url attempt has issues of one kind or another

I just went to the site and chose the categories you stated above and I was able to view the page.

I've reset the router, and I've cleared my browser cache, but I'm still getting the error. To reiterate, it happens only intermittently.

And if I'd read all I've read about Ultimate SEO -before- I installed it, I wouldn't have installed the blasted thing...