Hi Ash,
I have seen this issue before. Below are some links with some steps that show how to go about being able to tell your USB 6008 which firmware you want to load onto it. You will need a version of DAQmx, and DAQmx Base for the steps to work. It is up to you if you get the latest version of the DAQmx drivers, which I believe is at 8.6.1 now.
Let me know how you get on.
http://digital.ni.com/public.nsf/websearch/64BA7A1D64D3D5518625726D0066A780?OpenDocument Instructions for loading correct firmware
http://joule.ni.com/nidu/cds/view/p/id/950/lang/en DAQmx 8.6.1
http://joule.ni.com/nidu/cds/view/p/id/835/lang/en DAQmx Base 3.0
Regards,
Dan