I think you are making your life far too complicated at this point by worring about 64 vs. 32-bit, CMM vs OS, etc.
It's difficult to tell without seeing your test print in person, but personally I think your problem is with the image itself. I loaded it into Lightroom and looked at the histogram and would argue that the image is a full stop underexposed to begin with. By the time it gets to paper (which isn't backlit) the black areas look crunched up. Try lightening it by 1 stop (in Lightroom this is just +1 on the exposure slider), re-print, and see if you are happier.
Neil