To possibly more conclusively identify which file(s) are a problem, you could try a portion of what was suggested in post #2 of this thread:

Advanced Developer Option. (THIS APPROACH IS *NOT* NEEDED FOR MOST SITUATIONS!!!!)

While the built-in myDebug-xxxxxx.log method above is far more reliable and secure (since messages are never shown in your customers' browser), another way to help identify *where* an error is happening is to show the errors on your browser. The drawback to this is that your customers can also see the errors, and search engines might catch them too ... which could be embarrassing, AND WILL CAUSE YOUR SITE TO FAIL PCI SECURITY SCANS.
To attempt to show PHP debug errors on-screen, create and upload a new file, like this:
Filename: /includes/local/configure.php


Code:
<?php  define('STRICT_ERROR_REPORTING', true);
Then try to access your site again. You may see many warning messages on the screen.

Be sure to delete the /includes/local/configure.php file once you've identified the problem, lest you leave yourself with a security problem on your site.