When trying to install parental control for my kid's account I realized that my admin pw is not accepted in their standard accounts. Any procedure that requires a admin pw rejects the admin pw which otherwise works fine in the admin account. I used keychain first aid and did a lot of gambling-but did not succeed.
Are you using the German keyboard layout in all of your accounts? Does your admin password have a Z or a Y in it? Are you sure the keyboard layout in the kid's account has all the keys where you think they are?
German keyboard for every account, no critical characters. Did I mixed up anything with the keychains, access priviliges? I used the root account several times but can't remember doing anything supicious. Even with newly created accounts I'm having the same trouble.