Thank you, almut, this is indeed the case!

I have no control over the environment here, and the sysadmins have chosen to play games with which perl my she-bang invokes, so that it varies from environment to environment in this multi-platform shop.

Once you confirmed that I wasn't going nuts, then I knew that this HAD to be the problem, and I confirmed it. I have since developed a workaround which I intend to be the subject of my next posting.

Thanks again! — Eli-Sko