Full disclosure, I'm completely new to 3D design and I've spent a couple of weeks figuring out the right tools and learning some of the basics. Now that the OSX crash is behind us, I can actually save and load files.
My problem is that when I export the attached model as STL, ReplicatorG only sees the main body and does not see the cavity and entry point for the latching mechanism. When loading the STL back into IF, the entire object is there. So, I presume the problem to be in ReplicatorG but my simple workaround is to combine four components into one body and export that way. I've spent about an hour trying different things and searching the internet/forums and can't figure this out.