Hmmm.  I know importing Poser files uses a ton of system resources, especially RAM.  It could be an issue of not enough RAM.  I run with 2GB and sometimes I run into trouble if I try to import too many poser figures.  My last post to the galleries here had three poser figures and their clothes in it, transposed to C5 Pro it took about 20 minutes total for the software to get them imported, each one took progressively longer, nd I know that it made the system use a ton of virtual memory.  So you may simply be running out of RAM or virtual RAM.  Just a suggestion.