The version of comsat shipped with RedHat 6.0 was compiled
on a system with a different #define for _PATH_MAILDIR --
the shipped version was compiled with "/var/mail" when it
should be "/var/spool/mail".

Downloading the src.rpm and recompiling will fix that
problem.

Also, this version of comsat needs to be patched to allow
for the new devpts filesystem.  The patch is as follows
(this may need reformatting after the cut/paste):

--- comsat.c.orig       Mon May 19 18:37:50 1997
+++ comsat.c    Wed Jul 14 02:59:20 1999
@@ -203,15 +203,6 @@

        snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, line);

-       /*
-        * Um. This will barf on any scheme involving ttys
in subdirectories.
-        */
-       if (strchr(line, '/')) {
-               /* A slash is an attempt to break
security... */
-               syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%
s\"", tty);
-               return;
-       }
-
        if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) {
                dsyslog(LOG_DEBUG, "%s: wrong mode on %s",
name, tty);
                return;