Poser 4 is a far stretch from Poser5/6, but...I'd try bringing the min up to about %50, then %100.  You could also try to raise the Max., and do both.

I do'nt have my Tiff texs. open but remember it's the white that will stay put, and the black areas that dissappear. 

The Bump works the same way white - black.  You could try loading one of you textures there, alternatively, and/or along with the Trans.