I'm resubmitting my bug again after using version 4.0.10 of ncks on a MAC and getting the same error
/usr/loca/bin/ncks -d lev,0,0 -d time,0,0 -v lev -v lat -v lon -v omega http://goldsmr3.sci.gsfc.nasa.gov:80/dods/MAIMCPASM output.nc
nco_err_exit(): ERROR Short NCO-generated message (usually name of function that triggered error): nco_get_vara()
nco_err_exit(): ERROR Error code is -73. Translation into English with nc_strerror(-73) is "NetCDF: Malformed or inaccessible DAP DATADDS"
nco_err_exit(): ERROR NCO will now exit with system call exit(EXIT_FAILURE)
/usr/local/bin/ncks -d lev,0,0 -d time,1,2 -v lev -v lat -v lon -v omega http://goldsmr3.sci.gsfc.nasa.gov:80/dods/MAIMCPASM output.nc
succeeds (or anything after 0 for time). Time step 0 is Jan 1979 and time step 1 is Feb 1979.
Another user not on our computer system got this error when they ran 4.0.8 on linux. I don't think they had a later version of NCO. It worked for them on earlier versions
If it's helpful, the udunits library we have are 1.12.9 and 2.1.8 on the MAC.
Let me know if I can provide any more info.