Hello Mr.Lehn,
I have read also your another massage and I know you are using USB-6008.
Which version of Mac OS X 10.4 is installed?
Which versions of DAQmx Base are you linking?
I would recommend you to install the DAQmx 1.5 B driver from this page:
http://digital.ni.com/softlib.nsf/websearch/31593803B856C5AC86256FF8005FA4EB?opendocument&node=132060_US
Please let me know if the reinstallation from driver did not help.
Best regards
AmirG