Unit of measure error creating a purchase order

Our client changed the currency decimal places on one item from 2 to 0, using the GP utility. The unit of measure schedule is EA and there is an equivalency to EA of 1. On the price list screen, the default selling unit of measure is EA, as it should be. On the purchasing screen, there is no default unit of measure and nothing shows up in the list if we do a lookup on that field. If we try to type in EA, we get a message that EA isn't in the item's unit of measure schedule. We get the same message trying to put the item on a PO. What happened and what do we do to fix it?