What version of Adagio OrderEntry (including service pack release) is in use? A particular issue with record locking was fixed with the July 2005 OrderEntry service pack, though the error message was different than what you have reported. Please make sure the current service pack is installed (OE 8.0A - 050908). In fact, the fix had to do with the database interface file rather than the OE application specifically.
If the error continues to occur with the current service pack installed, please post here the exact function and timing of when the error occurs. Is it when the Find button on the Edit Items screen is clicked? Or using a finder or smart-finder field?
Also, what version of Adagio Inventory is installed? 8.0A or a previous version. Please also post the exact service pack version if the problem persists.