Have you tried making a very small change of some type to the poser file and then resaving it under a different name?  Also try a test render in Poser to make sure that poser sees all of the files it needs for the figure skin textures etc.  I run Transposer with Carrara 5 pro and Poser 6 with no problems on imports but it could have something to do with 4.1 I guess?   Also look and see how many frames you have and make sure there is only one frame, remove any extras.  I had a texturing issue last year which drove me nutz for 2 weeks until I figured out poser had for some reason created lots of frames and was saving the wrong one.  I hope this helps.

Rich