Bug: System.Collections.Generic.KeyNotFoundException

Error arises on starting:-
Unhandled exception: System.Collections.Generic.KeyNotFoundException: The key was not found in the collection at Wintellect.PowerCollections.ReadOnlyDictionaryBase`2.get_Item(TKey key)

Does not appear to be due to incorrect installation!

Software version: 4.0a and 4.0b.
Reported by Dave Hooton.
Forum link: http://community.logos.com/forums/t/12879.aspx
Also http://community.logos.com/forums/p/12836/100598.aspx#100598
http://community.logos.com/forums/t/12124.aspx?PageIndex=1

Status: fixed - metadata on server updated