【问题解决】
1、遇到这个问题,首先是google之。发现ubuntuforums论坛上也蛮多人出现这个问题。
有的人可以通过下面这个方法解决:
Hi all,
after upgrading my laptop to Hardy, all applications that required an administrative password failed to start. A button would appear in the panel, reading "Starting Administrative Application", but a few seconds later it would disappear without prompting me for a password.
I discovered that this can be fixed directly in the /etc/hosts file, where there should be two lines reading:
127.0.0.1 localhost
127.0.1.1 vaio
where "vaio" is the name of my computer. That solved the problem for me. Kudos to the forum of the Greek Linux Format magazine.