BIND crashes on reconfig or HUP, probably due to the way it instances a new, then destroys the old, back end when reloading itself. For Perl to use a single interpreter, this probably causes corruption of the interpreter.
I suggest changing things to use multiplicity/PERL_SET_CONTEXT or hack around this to not creating a new instance before unloading the last one.
Issue is fixed for both mutliplicity and non-multiplicity Perl's in latest SVN version.