MAT poses made for Poser 4 do not properly apply the bump maps in Poser 5 (unless they are *.BUM files). If you are using anything except a *.BUM file then you should use the bump node and NOT the gradient bump node in P5. Remember too that P5 bump maps are MUCH stronger than P4 can do, so to convert the P4 values, consider that a bump strength of 1 in P4 is about 0.001 in P5 and a setting of 100 in P4 is about 0.1 in P5. MAT Pose Edit v3.1 will have a batch conversion process which will convert P4 style MAT poses into proper P5 format including bump, reflection and transparancy settings, so an easy solution is on the way.