IMHO  the walk designer as well as IK are 'buggy' to say the least... i use them very spairingly and only in a seperate process to create speciffic movement(s) then i export to BVH and re-import to a scene i am building with no IK... i have noticed improvements in recent releases of poser, but i dont think IK or WD are stable enough to be of much use at the present time for anything other than 'roughing in' an animation, or for making static poses ...have patience and keep practicing , poser can achieve fantastic results but, as with any software,  it takes time to learn the ins and outs of the process... interaction between figures or objects is a hard thing to do in any software..

 

:O)

Y'all have a great day.