I have dbman running in a subdirectory on my main server, no cgi-bin because my host doesn't require scripts to be relegated to one. I didn't set any special permissions for the subdirectory -- and looking at the readme file, the only folder you need to set permissions on is auth, not the one where the scripts are actually housed.
I would suggest uploading it with the default folder permission (chmod the individual files, of course), and see what you get. Chances are it'll run fine.
Good luck!
'Salem ~
http://jherusalem.com