4
Right. before my time..
Perhaps if you state which version you have the developers will be able to help.
I notice with some older versions this for the preferences save etc that you need to change the file permission of config.php in /modules/system/cache/ so that it is writeable by the server. On unix/linux servers, chmod 666.
You would also need to chmod 666 all files under cache directory, apparantly in older version the main menu is stored in cache/config.php or something
Good luck..