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