[CE][SpawnRandomLoot] !!! No group configured fo

[ChicagoFaucet 0]

I have fooled around with the configuration files a bit for my server, but the original entries are stuff that I don't touch.  I just happened to be scrolling through the Log Viewer for my server, and I came across a good number of entries like this:

[CE][SpawnRandomLoot] (StaticTrain) :: !!! No group configured for 'StaticObj_Train_Wagon_Flat_Industrial_Barrels_DE', failed to spawn loot

I haven't touched the trains (or anything "standard") at all.  What does this error message mean, exactly, and should I be concerned about it?