You are running a perl script, on a mac, and you get this error, on a script that’s run without giving you that error before, eh?
I’m 99.99% sure the causer of your problem is that you are accessing a file on a non HFS+ filesystem, like say an external USB drive, or perhaps a network share from a windows box. That seemed to be the issue when I got it. The lack of resource fork can be safely ignored for files on such filesystems.
If you are seeing the error on a proper mac-disk, I dunno what to tell you. Hope you have good backups?