Well it shouldn't crash.  We are chasing down a similar issue on
another ticket.  When we get that sorted out we will send you a
patch to check if it fixes the crash issue.

As for the empty zone, it should be replaced if if a explicit
declaration comes it.  Similarly if a explicit declaration for a
potential empty zone is removes we should check if we should
instantiate it.

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org