procmail exited w/ EX_TEMPFAIL and stucked spamd processes

[Yedidia Klein]

I'm in the process of setting a new mail server on a Dual Xeon HT 
machine w/
RH Enterprise AS3,
sendmail 8.12.11
and SPAMASSASSIN 2.63 that run via procmail using spamd/spamc way.

I found this on my logs (/var/log/maillog)
Jun 29 16:54:49 mail-server sendmail[5512]: i5TC88xl005078: timeout 
waiting for input from local during Draining Input
Jun 29 17:02:49 mail-server sendmail[5512]: i5TC88xl005078: to=, 
delay=01:54:39, xdelay=00:10:00, mailer=local, pr
i=213649, dsn=4.0.0, stat=Deferred: local mailer (/usr/bin/procmail) 
exited with EX_TEMPFAIL

and there was also a stucked spamd process from this user..
sounds like spamc was stucked then sendmail get in time out for waiting 
to procmail...

any way to know why spamc/spamd was stucked / what could cause this 
problem ?

thanks,
--Yedidia