Questions:

Shared Hosting?

Assuming you're using a Apache Server...

I'm going to take a guess, could be a cache issue and/or .htaccess issue (mod rewrite)

If, Cache Folder:
Rename Old Folder: cache-old
Create New Folder: cache
Set Permissions: Usually, 777.
Test page.
Nothing? Attempt:

If, .htaccess Issue:
Rename Old File: htaccess
Test page.