sendmail errors

[Zanarotti at mit-multics.arpa]

Sendmail appears to be somewhat broken in 4.3BSD.  Ever since ATHENA
went to 4.3, we began receiving returned mail like the ones you got.

The "replacement out of range" is a result of an incompatible change to
the ruleset evaluator.  In 4.2, sendmail did not complain if the
replacement specified a string argument that did not exist.  For
instance, if the ruleset matched on three strings, and you gave it $4 in
the replacement, sendmail would not complain.  As a result, there are
buggy configurations out there, that sendmail is now complaining about.

The "endmailer:  no children" message is an intermittent error that has
been plaguing us for about a month.  Looking at the code, it looks like
sendmail is waiting for the delivery mailer, but the PID it's waiting
for doesn't exist.  This could be a kernel problem.  Has anybody tracked
this one down?