It is opening a file called 'password' (no extension)

"'X' requires explicit package name" means you haven't declared those variables (or you typoed them). That's what the text between the "(F)" and the "uncaught exception" is basically saying.

Use: my ($domain, $ip) = split(/,/); to declare them while you assign the values.

Note: the test.pl isn't for backups. It is for trying out new things to see what they will do. Use it to play around with split or regexes or whatever you're not sure about. Its all about having a tiny, clean sandbox to try things out in, where you know there is no other code to confuse you.