I have an assembly of parts built up to run a simulation.  I perform a geometry check -> boolean error, check geometry

so, I create a part to encompass the entire computational domain

systematically create a cavity from each component

find several failures (i.e. tube tangent to a plate -> line contact, etc)

remove all failures - generate 1 solid part with 18 cavities to comprise all 188 parts - this is essentially how Flow generates the fluid volume from everyone I've talked to

Problem: I can generate the equivalent of the fluid volume, but geometry check says "Boolean operation failed.  Check model geometry"

Any Suggestions?!?!?  

This is all in SW2009 x64 SP3 in XP x64