Granular Password setting error

i try to use Granular Password Setting in windows server 2008. i did all the
necessary configuration in ADSI Edit.but at the end of create object wizard.i
get this error :

Operation failed. error code: 0x20e7
The modification was not permitted for security reasons.
000020E7vcErr: DSID-03050681,problem 5003
(WILL_NOT_PERFORM),data 0