Hi Susan and Ryan,
thanks for help.
@Susans explanation:
All of my resources are assigned to a group "private" or "playground"; none is open, so that should be right?
I try to provide as much information as i could

Modx Version 1.03
PHP Version 5.2.13-0.dotdeb.0
DatabaseVersion:5.0.51a-24+lenny3
My Browser: Firefox 3.63
Windows 7
Facing the problems I installed a fresh version using the sample website, I did’nt make any changes beside the manager-resource-stuff
I also have a version here on my local pc using xampp, same thing.
I guess it must be something stupid I forgot but i have no idea.
So here are exactly the steps after installation:
1. Making a Manager-User "Erwin" with role "Editor"
2. Making Usergroup "parent"
3. Making Resource groups "privat" and "playground"
4. Combining User "parent" with group "playground"
5. Assigning all documents to "private" using DOC Manager (no recource is no open")
6. Set on Resouce to group "playground"
7. Checked the user tab "use access permission" is yes
8. logged out as admin
9. logged in as "erwin"
And "Erwin" can see and do everthing, (even if i chosed "Show protected pages" NO)
Maybe Erwin is God
I really have no Idea
Thanks