Can't find new VPP apps in Profile Manager

In late 2015 we purchased licenses for two free apps in Apple's VPP. These appeared in Profile Manager and have been used since then. Now the company wants to install another free app, but even though the app can be found in VPP's purchase history it still doesn't appear in Profile Manager. there have been no updates to operating system or server version.

The following error can be found in the logs for Profile Manager:

Sync of VPP data failed: -[PGConnection executeSQL:withParams:] (/SourceCache/RemoteDeviceManagement/RemoteDeviceManagement-876.6/Compiled/Fram ework-Models/Postgres/PGConnection.m:425): "Postgres error 22003 (ERROR: value "2593400542" is out of range for type integer