Authdaemond (defunct) error

[devrim baris acar]

Hi,
I am running a qmail.vpopmail sqwebmail system. At some time after I start
the system
, because of a reason I don't know yet the autdaemond gets into defunct
mode. And consequently the users can not login.
I have to restart the authdaemond.

What may be the problem?
Any ideas?

Devrim Baris Acar

 System conf:
 Redhat6.1 kernel 2.2.14 on a intel 550 mhz xeon.