Well, I can't anymore... that part of the problem is solved. I feel like an idiot for even asking.

The part here that help was "come up with the shortest complete program... which demonstrates the failure". So, having this file on the drive, I simply wrote the routine afresh and alone in its own .pl and I get it to work, including the eval. So I've brought the working code in and am certain it all works and that my actual bug is farther down and has to do with the complex structure I'm trying to access.

Thanks to both tilly and cLive for the assistance!