double messages?

[No Name]

I installed MailScanner with Clamav on a Solaris 8 (sparc) box running
Postfix as the MTA.  Often, but not always, 2 messages are delivered instead
of just one.  The first has the 'real' message, and the second is empty.
For example, a message just came through from this list from Marc Obaid, and
it was double.  The logs show the second blank message simply appearing, as
best as I can tell, although it seems that there may be 2 instances of
MailScanner trying to process the queue concurrently.  Has anyone seen
this behavior, and what can I do about it?

Thanks,

Jay Kusler
NSCL

Jun 10 08:53:48 jade postfix/smtpd[25820]: [ID 197553 mail.info] connect
from smtp.jiscmail.ac.uk[130.246.192.48]
Jun 10 08:53:48 jade postfix/smtpd[25820]: [ID 197553 mail.info] 4C8A6279:
client=smtp.jiscmail.ac.uk[130.246.192.48]
Jun 10 08:53:48 jade postfix/cleanup[25452]: [ID 197553 mail.info] 4C8A6279:
message-id= <1055249831.3ee5d5a71c23b at webmail.MUW.Edu>
Jun 10 08:53:48 jade postfix/qmgr[25436]: [ID 197553 mail.info] 4C8A6279:
from=<owner-mailscanner at JISCMAIL.AC.UK>, size=3460, nrcpt=1 (queue active)
Jun 10 08:53:48 jade postfix/qmgr[25436]: [ID 197553 mail.info] 4C8A6279:
to=<kusler at NSCL.MSU.EDU>, relay=none, delay=0, status=deferred (deferred
transport)
Jun 10 08:53:49 jade postfix/smtpd[25820]: [ID 197553 mail.info] disconnect
from smtp.jiscmail.ac.uk[130.246.192.48]

Jun 10 08:53:52 jade.nscl.msu.edu MailScanner[25538]: New Batch: Scanning 1
messages, 3650 bytes
Jun 10 08:53:53 jade.nscl.msu.edu MailScanner[25538]: Virus and Content
Scanning: Starting
Jun 10 08:53:53 jade.nscl.msu.edu MailScanner[25554]: New Batch: Scanning 1
messages, 3650 bytes
Jun 10 08:53:53 jade.nscl.msu.edu MailScanner[25538]: Uninfected: Delivered
1 messages
Jun 10 08:53:53 jade postfix/qmgr[25479]: [ID 197553 mail.info] 17D259380:
from=<owner-mailscanner at jiscmail.ac.uk>, size=3467, nrcpt=1 (queue active)
Jun 10 08:53:53 jade.nscl.msu.edu MailScanner[25554]: Virus and Content
Scanning: Starting
Jun 10 08:53:54 jade.nscl.msu.edu MailScanner[25554]: Uninfected: Delivered
1 messages
Jun 10 08:53:54 jade postfix/qmgr[25479]: [ID 197553 mail.info] 5616F937E:
from=<owner-mailscanner at jiscmail.ac.uk>, size=2603, nrcpt=1 (queue active)

Jun 10 08:53:56 jade postfix/local[25558]: [ID 197553 mail.info] 17D259380:
to=<kusler at NSCL.MSU.EDU>, relay=local, delay=8, status=sent
("|/usr/nsclsbin/procmail")
Jun 10 08:54:03 jade postfix/local[25577]: [ID 197553 mail.info] 5616F937E:
to=<kusler at NSCL.MSU.EDU>, relay=local, delay=15, status=sent
("|/usr/nsclsbin/procmail")