In Poser 7, in Geometries->props folder there is ground.obj and in the GreekBath set there is Ground.obj in the Geometries->Marforno->GreekBath folder. It may cause a problem.

Bath Base in the figures library is the filling to your big empty area, which calls for Base.obj (which you could import directly from the geometries folder), which might be the problem, as there is a base.obj in the Poser 4,5, and 7 Geometries->deform folder (Poser 6 has base.obz), which I think is for the magnets base. Try renaming the GreekBath Base.obj and adjust the reference in the Greek Bath .cr2 files and see if it loads then.