[Exim] first_delivery

Hello all,

    I'm having problems with filters, specifically
virus checking with AVP. From what I can tell,
the 'not first_delivery' line is not working in my
filter.
    What happens is the mail changes to
nobody@??? (because of the filter) and
continues to loop.  The kavkeeper program adds
a header everytime, and I end up having to kill
exim -- finding many of the same headers...

Any advice would be much appreciated....


---SNIP---
## My filter

# Exim filter <== do not remove this line !
if not first_delivery
then
        finish
endif
 pipe "/usr/local/share/AVP/kavkeeper/kavkeeper -s $sender_address -r
$header_to -m sendmail"
finish

## My Exim config
#Main config
message_filter=/usr/local/etc/exim/virus_filter.exim
message_filter_pipe_transport=virus_filter_pipe
.
.
.
#Transports
virus_filter_pipe:
driver = pipe
return_fail_output
---SNIP---


Thanks again,
Dave Raven.