The backports kernel: linux-image-2.6-686 (2.6.32+27~bpo50+1) and unstable kernel do not have all of the comedi modules compiled in, but are compiled into the latest Debian stable kernel Image After talking with the comedi development group: http://groups.google.com/group/comedi_list/t/c68f90083f7f76d3 It looks like all the comedi config options need to be selected in the latest kernels. Brandon