if you're making a haloce map, then the cause MIGHT be because one of your tags are corrupt.
I'm not absolutely sure though, because usually tool shows you which kinds of tags are not 100% complete like where it says:
Quote: overlay item 0 for cmt\hud\interfaces\weapons\single\portable turret handheld re
ferences an invalid sequence
units must have models and animation graphs
crosshair item 1 for halo3\hud\weapon interfaces\sniper rifle\sniper rifle refer
ences an invalid sequence
crosshair item 1 for halo3\hud\weapon interfaces\sniper rifle\sniper rifle refer
ences an invalid sequence
In your debug you just posted. I'm sorry i couldn't help much, because tool doesn't tell much info when you get exceptions, sorry!