won't write sendmail.in.pid

[Marc Lucke]

CPU speed: PIII, 500MHz
Memory: 452MB
Operating System: Fedora Core 5, 2.6.17-1.2157_FC5
MailScanner version: 4.51.5-1
MTA version: sendmail-8.13.7-2.fc5.2 (RPM installed FC5)

[blahblah~]# service MailScanner status
Checking MailScanner daemons:
         MailScanner:                                      [  OK  ]
         incoming sendmail: head: cannot open `/var/run/sendmail.in.pid'
for reading: No such file or directory
                                                           [FAILED]
         outgoing sendmail:                                [  OK  ]

Despite the above, I am receiving email and it is being filtered for spam
as normal.  /var/run/sendmail.out.pid is written and works fine. 
/var/run/sendmail.in.pid does not exist at all - whether MailScanner is
started or not.  INPID is defined as /var/run/sendmail.in.pid as per
default.

What could this be?