[Exim] exim & amavis

Hello..

I have small problem with exim & amavis...

When some users send emails to my server and receiver address exist then all is ok. When not exist, sometimes exim leave copy of reply mail into own spool quene. Message has not processed by Amavis Router and exim FREEZE it..
log from sigle freeze mail:

2002-03-13 23:35:26 <Mail@sender>: amavis transport failed: Child process
of amavis transport returned 255 (could mean shell command ended by signal
127 (Unknown signal 127)) from command: /usr/sbin/amavis
*** Frozen (delivery error message)

Exim is 3.12, debian, amavis-perl-11

Can you have any idea how i can eliminate this problem?
daily I have a "couple" :(( of this mails..

and any one problem:
in /etc/exim.conf I have this lines:
smtp_verify = true
sender_verify = true
sender_verify_reject = true
sender_verify_fixup = true
receiver_verify = true


and all works ok, but when I installed amavis exim not verify receiver local-part.. why?

Have Nice Day
Roxik