Well, if the texture is in .exe format install it to your desktop and look inside, there should be a folder called "textures."  Look at the name of the folder inside that folder, inside there will be your texture.  If you want to see where that is installed in poser, open up the poser folder hierarchy, click on runtime, then textures and find the texture folder with the name you saw earlier, and inside will be the actual texture file.

That was a little convoluted, sorry.