Printing a content-type is a good idea, but it won't always work -- you'll want to turn output buffering off, just in case something throws an error before the print buffer gets flushed, and even then, it might not get to the print statement if something happens in a BEGIN block. (and well, 'use' counts as a BEGIN block.

Based on the error message, I doubt it's a permissions problem, but I would make sure that the file passes 'perl -wc filename' from the command line -- it'll let you know if there's something blatently wrong with it (like missing modules, which is a distinct probability when switching systems, even when the perl versions are the same)

Oh -- and for debugging, I love CGIwrap. It handles processing limits on my CGIs and keeping them from running as the webserver, and a quick change to the URL, and it'll spit debugging info back to you.