more braille display woes!

[the Pawpower Pack]

Hi, I'm the one who has been unable to successfully run a Syncbraille  
on my Macbook.  I am now trying to run a Pacmate 40 display on the  
same machine and no go.  I have checked the box under universal which  
allows for assistive devices.  I have gone into the VO utility and it  
says that there is no display detected!  The Pacmate pops up with  
Pacmate 40 when I plug it in but the Mac doesn't seem to recognize  
it.  Any ideas?
My USB ports do work, and I've tried this display in both ports and  
nothing.

Thanks
Rox