First, we will want to make sure that you have the latest NI-DAQ driver that still supports C program. That driver should be v4.9.4 and can be found from the link in the previous post (or here http://www.ni.com/support/daq/mac/macversn.htm).
After verifying this, I would try to restart the computer without your hardware installed to check if it is a hardware/NI-DAQ configuration issue or if you just had a bad install of the software. If it still does not work without the hardware than you can attempt to uninstall/reinstall NI-DAQ v4.9.4.
Finally, the problem may lie with in a conflict with the extensions on your MAC. If you are familiar with troubleshooing MACs, then you can disable all but the core extensions and see if you can get the computer up and running
that way. Below are a few KnowledgeBases that discuss some of these issues:
Computer Hangs While Trying to Install NI-DAQ or LabVIEW on MacintoshMy NI-DAQ Crashes Either at Boot (4.x) or When Loading (6.x) on the Blue and White Power Macintosh G...Regards,
Michael
Applications Engineer
National Instruments