What does this error actually mean? It's spammed countless times in my Papyrus Logs.

[01/17/2013 - 10:56:07PM] warning: Assigning None to a non-object variable named "::temp4"
stack:
[DarkBrotherhood (0001EA5C)].darkbrotherhood.OnUpdate() - "DarkBrotherhood.psc" Line 220

Seriously, half my logs are this message. Anyone made any progress on figuring this out?