The script itself isn't affected by this error (at least so it seems), the file is being opened and everything seems well.

Before making such statements, check for the return value of open and close first:

open FH, "test.txt" or die "Can't open file: $!";
close FH or die "Can't close file: $!";
[download]

or even use Fatal qw(open close);

I can't answer your question though.