Are you using OS9 in classic mode? If so, NI-DAQ will not work with OS9 in classic mode. You will need to boot directly into OS9 to get the hardware and NI-DAQ driver to work.
Also, have you tried NI-DAQ 6.6.1 or just NI-DAQ 6.6? I would make sure to try NI-DAQ 6.6.1 which is the newest version of NI-DAQ for Macintosh. I've included a link to where you can download NI-DAQ 6.6.1 below. I hope this helps.
Current NI-DAQ Driver Downloads
http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C128D?opendocument
Regards,
Todd