Sorry It took me two days to get back to this.
I've been getting my ducks in a row, so to speak.

I've had problems doing it both ways.

1st the error I spoke of getting.
It is after parenting everything via "HE" to my Bottom floor.
The error "Multiple Root Actors found, check parenting".
My only option then is "OK" then all my nails loosen & my house goes haywire. :)

I believe I solved this.
6 of the items were figures I created from Parented props then loaded onto me house. My work around was to create a new figure from these, though it took one texture accross it's materials, (see below), it was one material so no biggie.
I parented the remaining props to the bottom floor and now can move the entire house from it. :) Very good big step forward.

If I try to make a new figure either from "HE" or export, my new figure comes out all wood, no other textures. (I can live with loosing trancparencies and reflections re; as Geep stated).

As a test I created a new creation using those props with multiple textures and exported to an obj. Once again it came in with one texture.

The textures are in two or possibly three different locations all within Posers main texture folder.
Can't think of any other possible reasons.
Next to other things on my agenda these next few days I'ld realy like to figure this out.

MINFIG.
All previous trys included moving all figures & props.
I haven't tryed to do this excluding the 6 figures I speak of above. I will ASAP.
Parenting everything makes Poser unstable, good word. ")
And then when saving or closing... Crash. :(

I have been succesful at using MINFIG and definetly see it's use in past & future projects. Many Thanks.
Hopefully I will figure out this current prob thus widening it's usefullness. Thanks.

One other note maybe of importance...
Using Poser 6 & a Mac

Much & many Thanks! Scott