Fixed multiple syntax errors, and added code to parse the new $code value.

#/usr/bin/perl
use strict;
use warnings;
my $code = 'ITEM_1 ,ITEM_2 ,ITEM_3 ,ITEM_4 ,ITEM_5 ,ITEM_6';
my $dir = '/local/usr/prod/';
my $exp = 'PRODUCTS';

for my $c (split /[\s,]+/, $code){
    my @filelist =glob "$dir*$c*$exp*failed*";
    foreach my $oldname (@filelist){
        next if -d $oldname; # Update - corrected this - was missing $
+oldname!
        (my $newname = $oldname) =~ s/sold/ordered/;
        rename $oldname,$newname
            or warn "can't rename $oldname to $newname: $!"
    }
}
[download]

You should consider using @ARGV to pass arguments into your program. see perlvar.