Error with new page

I’m using Yoast WordPress SEO and it is a great plugin so I hope that isn’t the problem. When I rename a page using Yoast and then try to view it I get the “not found” page. I named a page “beatles” when I click on the link in the menu the address bar goes to “beatles/BeatleIndex.php” which isn’t there so that’s why there is an error.
My question is why is it looking for the “BeatlesIndex.php” file?

Before I installed WP I was running an image script called Revolver made by Tubatomic. I had a folder called “beatles” and there was a “BeatlesIndex.php” file in that folder. But I have deleted that folder and I thought everything else associated with the Revolver script, but maybe not. I’ve looked through my files to see if I’ve forgotten something.
Is it possible that WP is reading something that is making it look for the BeatlesIndex.php file? No other page name does this, just beatles.

Any suggestions?
Thanks,
jim