MyDocs in normal mode is fat32 and user:users installation of n9qt create some folders in MyDocs without any problem. Try to add user:users to MyDocs like Ancelad suggested you.
id -u => 0 touch ~user/MyDocs/foo => touch: /home/user/MyDocs/foo: Permission denied aegis-exec -u user touch ~user/MyDocs/foo; ls -l ~user/MyDocs/foo => -rw-r--r-- 1 user users 0 Sep 9 21:38 /home/user/MyDocs/foo