Has anyone had an issue with importing data and permission

Has anyone had an issue with importing data and permission issues -
I have been importing business listings into my MU installs - 300 records at a time for the last month --- some 200,000 listings --- without any issues --

Then all of a sudden -- they started timing out and not working --- Hostgator is looking at this and says it is a permissions problem and has something to do with admin_ajax.php.

I have installed word fence lately -- but even with it uninstalled - the problem still exists ---

Anyone have any idea