Thank you very much everyone for your feedback!

I'll respond here to your suggestions, and then offer a partial possible cause of the problem that I think I've located at the end, here. If what I think is happening makes any sense and anyone knows how to correct it, I'd be most grateful! If what I'm saying makes no sense, I'd also appreciate being told, to save me even more time barking up the wrong tree!

I apologize for any lack of clarity in explaining my issue: being somewhat new to Poser means that maybe I don't know exactly what need to be specified when explaining what's going on. I've made every object in the scene "invisible" by clicking all of the "visibility" options in the "Properties" of the Parameters window.so that they are unchecked ("Visible", "Visible In Raytracing", "Casts Shadows", all not checked). This makes them disappear from the Preview window (and, as far as I can tell, from the possibility of being rendered).

I've tried rendering in both Poser 4 and FireFly modes, and the problem is the same in each.

When rendering, I am looking at the scene through the Main Camera, and not one of the other ones (although none of the other cameras are obstructed by buildings, either, because I've made all of the other buildings other than the one I need for the scene invisible, as explained above).

The wall that raven has suggested I make invisible is part of the same Object as the building the figure is standing in front of, so when I make it invisible, she winds up standing in front of nothing - removing it DOES solve the problem of the blank wall render, but my figure is now rendered almost entirely off-screen again, as in my second post above.

I have had a little insight, I think, but I have no idea how to correct it. Hopefully one of you helpful folks can point me in the right direction:

At this time, I think that the issue has something to do with the camera's focal settings. In trying to rectify the problem, I've been playing around with just about everything, and it seems like the initial problem of the blank wall and the second problem of the central object of the Preview window being rendered off-screen are the same problem. Poser seems to be rendering things to the LEFT of what I'm actually looking at in the Preview screen (so the blank wall being rendered isn't something directly between the camera and the central figure - it's the wall to the left of the camera.). If I re-set the Main Camera's focal length to 38, then I get a render fairly close to what I'm seeing in the Preview screen (except for that stupid "fish-eye" effect). When I increase the Focal Length, my figure gets rendered to the right of screen.

I'll post 2 examples, with the building behind the figure made invisible and the Focal Length at 70, and we can see the problem.

I'm not sure why changing the Focal Length would make Poser render as if the camera was at a different angle... if that is the problem, is there a fix?

Thank you to anyone who has applied any of their time to helping me with this one. If I'm right, then hopefully the answer is close....