I guess you have already read the how-to #12.. If not then perhaps that will help getting it to work.
Part of the how-to is kind of confusing to me though..
Quote:
By using multiple passwords you can give some friends access to some directories and e.g. your family access to other directories. The advantage is now that these two groups can now have access to the same galleries as well! Or you can protect all galleries with a kind of "super password" and a couple of directories with a 2nd password for access of only an area.
..I don't really understand how different passwords = different access rights. I thought that was only associated with different users.
I've not looked at the php that deals with private.txt but there very well may be a pw qty limit that isn't documented... In which case I guess you're in a position to be able to experiment and find out the limit.