Strange 404s in GWT - "Linked From" pages that never existed

[Fuel]

I’m having an issue with Google Webmaster Tools saying there are 404 errors on my site.

When I look into my “Not Found” errors I see URLs like this one:   Real-Estate-1/Rentals-Wanted-228/Myrtle-Beach-202/subcatsubc/

When I click on that and go to the “Linked From” tab, GWT says the page is being linked from http://www.myrtlebeach.com/Real-Estate-1/Rentals-Wanted-228/Myrtle-Beach-202/subcatsubc/

The problem here is that page has never existed on myrtlebeach.com, making it impossible for anything to be “linked from” that page.

Many more strange URLs like this one are also showing as 404 errors. All of these contain “subcatsubc” somewhere in the URL.

My Question: If that page has never existed on myrtlebeach.com, how is it possible to be linking to itself and causing a 404?

[GlobeRunner]

It's quite possible that at one point there was a link there--because the page rendered for some reason. I would crawl the site yourself using a crawler (there are several available) to make sure that the page isn't reachable from, perhaps, a bad link on the site.

Check the archive.org to see if the page existed at one time or not.

I would also take a look at the page's server header again to see if the site is showing a 404 error or a "200 ok" along with a "page not found". It's possible that the page doesn't exist but it delivers a "200 OK" server header anyway. Another option is that it might be in your sitemap.xml file.

When in doubt, if the page doesn't exist, I would mark it as fixed in Google Webmaster Tools and watch if it comes up again. If it doesn't come up again as an error, then I wouldn't worry too much about it.