Is there a MIVA built in protection that limits the number of orders one "computer" can create within a day or specific time frame? If so, can that be modified?

I have a client that gets phoned in orders and then enters those orders himself online into his MIVA storefront. He just encountered a problem. He successfully entered 15 (not sure of exact #) different orders and with the next order, the Basket will only say "empty" no matter what. After going through the other possibilities including the possibility of a corrupted page, etc., I thought perhaps there was some kind of built in safeguard.

Anyone know? Can't find anything in the documentation.....

Thanks for the help!