lucy24 - 12:04 am on Aug 12, 2012 (gmt 0)

The host had two files in the public folder when I moved to that host that were called 404.shtml and 403.shtml. But they were causing issues with the index.php file I had

Hmmmm. I think we need to know a little more. There shouldn't be any connection between an index file and an error document.

Among other things, that "shtml" extension implies the files are including stuff from elsewhere. Advertising, possibly. But if the host didn't want you to edit the files, they wouldn't have been accessible to you in the first place.

the error log showed that the server was looking for those error pages. So, I assume I need to replace them

You generally have two options in shared hosting.

#1 Use files with the default name in the default location-- but format them nicely to match the rest of the site. (wilderness, I think gg's and my hosts may be one nano-notch above yours in this respect. The filename and location are built in-- but it's in your own userspace, so you can change the content of the document.)

#2 Use error documents with your own choice of name and location, accompanied by the "ErrorDocument" line in htaccess.

When there is a 500-class error, the server either can't or doesn't look at your htaccess, so it only looks for the default file specified in the config file. I've seen the same type of error myself-- but it's not the normal response to a 403. It only happens when
:: ahem ::
:: cough-cough ::
I've made a mistake somewhere.