setting up Smartlist with sendmail

I am setting up Smartlist on a new RedHat GNU/Linux 2.6.18 machine with 
Sendmail.  The configurations are like:
1. /etc/aliases:
newlist: "|flist newlist"
newlist-request: "|flist newlist-request"
2. /etc/smrsh/flist -> /usr/local/slist/.bin/flist
3. /var/mail/.etc -> /usr/local/slist/.etc

When tested mail to "newlist", it's not sent to the list but appended to 
/var/spool/mail/mail (nothing written to /usr/local/slist/newlist/log , 
nor any mail deposited to /usr/local/slist/newlist/archive/latest/)

The /var/log/maillog says mail accepted for delivery, then next line it 
says "timeout waiting for input from local during Draining Input"

Any suggestion what could be the problem and where should I check further?

Thanks,
Zhiliang