求助--在普通用户下无法更改密码?

auty

[auty@localhost auty]$ passwd
Changing password for user auty.
Changing password for auty
(current) UNIX password:
New UNIX password:
BAD PASSWORD: is too similar to the old one
New UNIX password:
BAD PASSWORD: is too similar to the old one
New UNIX password:
BAD PASSWORD: is too similar to the old one
passwd: Authentication token manipulation error
[auty@localhost auty]$
改了好几次都没有改成功!
老密码是6位的,想改英文+数字 7位密码
请高手指教.
FC2