When attempting to post OE orders, client receives error message, "Error writing record to I/C Item Location. Record does not exist."

DIC is OK in both OE & IC. This error does not occur when posting orders in sample data. The error happens on all stations. This occurred from one day to the next at a time when there were no changes on the network and no new software installed.

The server was rebooted in case any of the 3 ICILOC files were locked. This did not resolve the problem.

Has anyone seen this or a similar problem?

OE 8.1E (130322)
IC 8.1D (120126)