The problem is in the dh_install calls in the rules. I was able to fix this by applying this patch:
diff --unified xymon-4.3.10/debian/changelog xymon-4.3.10-sz/debian/changelog
--- xymon-4.3.10/debian/changelog 2012-08-04 05:13:20.000000000 -0700
+++ xymon-4.3.10-sz/debian/changelog 2012-10-10 18:42:25.662517487 -0700
@@ -1,3 +1,9 @@
+xymon (4.3.10-sz) unstable; urgency=low
• + * Fixed Debian/Ubuntu build to put init and logrotate scripts in the right packages.
• + -- Kraig Amador <user-94a3294e96d3@xymon.invalid> Wed, 10 Oct 2012 18:42:00 -0800
• xymon (4.3.10) unstable; urgency=low
* rev 7164
diff --unified xymon-4.3.10/debian/rules xymon-4.3.10-sz/debian/rules
--- xymon-4.3.10/debian/rules 2011-03-08 09:20:28.000000000 -0800
+++ xymon-4.3.10-sz/debian/rules 2012-10-10 18:50:14.663024230 -0700
@@ -137,9 +137,9 @@
rmdir $S/usr/share/man/man7
dh_installdebconf -a
# use the old file names for now
- dh_installlogrotate --name=xymon-client -a
- dh_installinit --name=xymon -p'xymon' -- defaults 98 02
- dh_installinit --name=xymon-client -p'xymon-client' -- defaults 98 02
+ dh_installdebconf -a
+ dh_installlogrotate -a
+ dh_installinit -a -- defaults 98 02
dh_installman -a
dh_link -a
dh_strip -a
--
Kraig Amador