I've had zoneminder running now for several days without making any changes. Then last night it started this...
Use of uninitialized value in numeric ne (!=) at /usr/lib/perl5/vendor_perl/5.8.8/ZoneMinder/SharedMem.pm line 503
Typically things only break after I have made a change, not after several days of smooth running. Random, unexplained, sudden breakage make me doubt the trustworthiness of zm under any circumstance.