That errors because of my commit to ImprovedRWF and I didn't notice it because my BigWigs isn't split up and LOD. I made the commit because a change in BigWigs caused ImprovedRWF to not detect BossBlock at all. I'll try to come up with a better solution but I think part of ImprovedRWF needs a complete rewrite due to changes in BossBlock.
A temporary solution could be to add BigWigs_Plugins to the OptionalDeps. Actually it looks like somebody already fixed this but I'm not so sure its a good fix since I think the spam filter will be disabled unless BigWigs is active when it loads.