what is the contents of
cat /etc/release
Have you used http://groups.google.com/advanced_group_search in the
Mandriva group.
I do clean installs, and have yet to have your problem, after 10.x release of Mandrake.
You may find dinking with permissions can cause problems, or you will
notice they change back, thanks to msec - Mandriva Linux security tools
sudo is a tool to allow you to run root commands.
Those are a special set of permissions.
Click up that Home icon (Konqueror) and pick file in your account to
play with.
Right click it, Properties, Permissions, Advanced Permissions
and there are the Special bits. Change one, click OK, Ok
click up a terminal and do a
stat -c %a Your_file_here
to see which bit is which.