Okay, here's what I'm babbling about:
  I'm using an old Poser World character,  PWFW Queen Elizabeth.
(It's so old, the zip isn't even arranged into a runtime directory structure, it's just folders dumped into a zip. So old, there's no readme beyond generic Poser file structure info, not the actual files included in the content)
Now, before I describe the problem, I want to emphasis that we can rule out the runtime being installed wrong, because I installed the files correctly, was able to get the "right" result (in terms of, the figure/objects=character loading properly).

So, here's the problem: When the figure/character loaded the first time, I was prompted for an object file. I did a search on my Explorer (and for &^%$'s sake, why doesn't Poser incorporate a file name folder search into it's user interface, I will never know)  and found some similar but not exact files. The one I chose was a good guess because the result was that it looked just like the thumbnail render that came with the content. Okay, what's the problem? The problem is, I wanted to keep experimenting, so I  saved the "good" result as a poser scene, then in a new scene loaded the other version of the figure/character (there are two), and selected a different obj file this time. Long story short, at this point Poser decided to "settle" on this object, and will not prompt me for the object anymore. Fine, try refreshing the runtime with the content again...nope. Fine, now we know the change doesn't take place in the content runtime directory. Fine, replace the whole darn POSER 6 folder. This "works":  I can get back to beng prompted, just once, but Poser will still "settle" on the selected object, and so I am prevented from choosing somethingelse (.obj) even if my choice results in garbage;  it sticks.

Question: where is the info that tells Poser to "settle" (associate a particular obj file)? How can I bypass this, so that I will be prompted each time for that obj file? Or, what is an equivilent way to accomplish the same thing. I would like the freedom to bypass, but only at will. In other words, its a nice feature when you want to load something correctly just once and forget about it, but it's not if you make a wrong choice and can't get out of it.   
Thanks in advance, mucho appreciado!

In a figure file (CR2), the OBJ file is associated in the 'figureResFile" lines (there are two, one being redundant and used as a delimiter of sorts).

Unfortunately, you can't do this complete figure .obj substitution in Poser - the entire figure depends upon the geometry in the obj file (the groups, the verts, the polygons, their orders and counts).  Morphs would be immediately destroyed since they are directly tied to the geometry.  JPs would need major tweaking.  So forth and so on.

So, the only resort here is to edit the CR2 file directly.  You can use a text editor or something like Dimension3D's PoserEd (much easier to use than text editor).

A quick way to force the search is just to change the figureResFile lines
to a file that you can guarantee is nonexistent.

figureResFile "xjio5jijijriew8thioen2tijfifjfi1dsjff.obj"

Thanks for the help!  Look at that, 5958 and 5960...posts, that is. Neck and neck  :)

Apparently, the first figureResFile line is the original, and the second gets updated with the user's selection. Emphasis on apparently, I'm toughing this out  on notepad text editor.

Thanks again for the tips....looks like a good niche for a python script, to me :)

No.  Both are always the same reference.  The second acts as a notification to Poser that the declaratory section (declares the actor and geometry) for figure actors is finished and that the next set of actors will be definitive (defines the Poser body part, JPS, etc).  In multi-figure files, the figureResFile lines act as delimiters between figures in both the declaratory and definitive sections.

All that said, you probably only need to change the first one as this is the one used by Poser to make the geometry reference - the second is ignored in this respect as far as I have experienced.  But I'd still keep them matched.

Okay, perhaps this explains my anomolies. Going back to the original content file, here are the first and second lines:

figureResFile :Runtime:Geometries:ZygotePeople:blMilWom.obj

figureResFile :Runtime:Geometries:pwfw:sistervikki2elizbth.obj

I think I know what to do now :)

thanks a lot !