Okay, so I asked my host about anything on their end that would cause this and they said they configured the server to allow huge files to be downloaded. They also suggested I change the Maximum file size in the Admin > Config section of zen cart.
So, now I cannot log into the admin area (username & pass just go blank), and when customers try to log into the store, it says "There was a security error when trying to login."
HELP PLEASE!




