Magento

I have upgraded a large (30,000+ products) database and the catlog loads and searches fine however when you goto create a new order in the admin area, regardless of whether its an existing customer or a new customer, there are no products initialy bought up and the search by fields e.g. SKU brings now products up.

I have looked at the Firebug Net output for the ajax call and the returned html says that zero products were found.

Any ideas on where to start looking?