If you can run this in a console after logging in:
x11vnc -password (mypassword)
without having to enter a password then you should be able to create a bash script to run that command and set it to autorun every time you login. If you need to manually enter the password after running:
then a simple bash script won't work. You still haven't answered which desktop environment(DE) you are running, eg kde, gnome, etc. Each DE has it's own way of setting up what autoruns on login. Since mandriva defaults to kde, I assume that's what you are running. In that case, after making your script, you would just place it in /home/<username>/.kde/Autostart. Every time you login to kde, the script will run.