Import/export .flt files error

Hello.
I’m not sure if this is the right place to post rhis, but I’m having trouble importing and exporting .flt files.

I have a .flt file I bought.
I open this file in blender 2.46, when this was supported.
I want to keep a single object in this file, and make it bigger.

When I imported the first time, I had to install Python. I installed 2.54.
Now I could import and edit the flt file. Yay!

But when I remove the excess junk, and make the object like I want it, I export it.
I then see in Windows Explorer that the file is 5kb, which is unreasonably tiny.
When I try to import it back into blender, the object is all gone. Not there.

I’ve also tried to remove piece by piece, but then I sometimes ended up with just a square when importing, even though that was not my object at all.

Anyone got any fixes or ideas?

Much Appreciated
-mymusicmanager