VLC for iMac new installation

[sturmhafen]

we just got our new iMac (El Capitan) and we're trying to get the blu-ray (LG B14) to function. Various forums suggested VLC to run. So we just downloaded VLC (newest version, obviously) and it gives an error "file reading failed" and "your input can not be opened". I've tried following the instructions on the wiki.videolan support page (run the "remove preferences" script, it says)...except I can't find that anywhere. Obviously I'm doing something wrong. Help?