Problem changing AD password

When I go into system preferences to change a users password I get the following error: You cannot change your password to the password you entered. and then some more text telling me to see my administrator about complexity blah, blah..... The password I tried to set uses 8 total characters including one cap and one number - doesn't work. However, if I simply put in 9 x's it will work. On the AD DC - the security policy is set only to require a minimum length of 4 characters and complexity requirement is disabled. Any idea where the mac is picking up that it needs more than 8 characters? Also if I set the flag to change on next login on the AD DC, it tries to do so on the mac, but I get the shake when I enter the new password and verify - could this simply be the same problem? It does not seem to be as when I enter the 9 x's it is will not let me in.... Thanks, Matt