htaccess problem

I know this is not exactly a WP question, but I’ll give it a try here anyway.
For some reason I seem unable to work with htaccess properly, that is to say, some things work, other things don’t.
I have a test site that I like to put behind an htaccess password. Not too difficult, but for some reason the password isn’t recognised. Yes I used a password file with an encrypted password (user:encryptedpassword, nothing else in the file) and edit the htaccess that is already there. I also had that issue with the demo mode plugin, newer versions of Ask Apache, but in the end I got an old Ask Apache to work properly and I use a hotlink protection plugin that also works. Therefor I guess it’s me. Does it have something to do with file permissions, file locations or something like that? I used some of the many automatic htaccess and password file generators, so it can’t be bad coding. What then?