I also couldn't find a "Barnard.zip" anywhere, but I did find this .tgz version:
https://osdn.net/projects/sfnet_skyc...g_barnard.tgz/
There is a header b.hdr, index b.ixr, and .dat files inside. As merlin66 suggests, your "barnard.zip" is not in the right format.
Copy the unarchived "barnard" folder that's inside into the cat directory, then add it with the Setup > Catalog > Catalog menu. Click on the folder after the path. Navigate to b.hdr and open it. Turn on the bullet to green. Click Apply, OK.
Turn off the SAC because there's another B33 in that catalogue.
Tested in Win7 x32 with version 4.0-3575.
--sutekh