When the process tries to write to the socket after the connection has

been closed, it gets a SIGPIPE signal. Without custom signal handling,

the default action is to terminate the process, see signal(3).

signal(3).
Basic socket programming issue, the author sucks. Try the patch below ;)
Daniel
Index: pfstatd.c

===================================================================

RCS file: /var/cvs/pfstat/pfstatd/pfstatd.c,v

retrieving revision 1.1.1.1

diff -u -r1.1.1.1 pfstatd.c

--- pfstatd.c	11 Jan 2007 16:01:58 -0000	1.1.1.1

+++ pfstatd.c	26 Mar 2008 17:58:05 -0000

@@ -39,6 +39,7 @@

 #include

 #include

 #include

+#include

 #include

 #include

 #include

@@ -97,6 +98,7 @@

 	}

 	if (argc != optind)

 		usage();

+	signal(SIGPIPE, SIG_IGN);

 	if ((fdp = open("/dev/pf", O_RDONLY)) < 0) {

 		fprintf(stderr, "open: /dev/pf: %s\n", strerror(errno));

 		return (1);