Oh yes, I found it:

foreach my $file (@fileet) {
        my $newfile = $file;
        $newfile =~ s/ä/ä/g;
        $newfile =~ s/ö/ö/g;
        move("$path/$file", "$path/$newfile");
}
[download]

The error was here

move("$path/$file", "$path/$newfile");
[download]