Few improvement ideas. Untested:

sub dispatch_closing
{
    my ($line,$fw,$key,$HR_record,$os)= @_;
    
    my $brace = ($line =~ /SERVICE_APPLICATION_EXECUTION_COMPONENT|UNX
+/ ? '>' : '');
    
    if ($line =~ /SERVICE_APPLICATION_EXECUTION_COMPONENT|WEB_APPLICAT
+ION_EXECUTION_COMPONENT/)
    {
        while(my($k, $v)=each %$HR_record)
            { print $fw "\tENVIRONMENT_VARIABLE Id=\"$k\">${v}ENVIRONM
+ENT_VARIABLE$brace\n" }
        
    }
    if (($line =~ /UNX/ && $os eq 'unx')
    || ($line =~ /WNT/ && $os eq 'win'))
    {
        while(my($k, $v)=each %$HR_record)
            { print $fw  "\tRESOURCE Id=\"$k\" Source=" . substitute($
+v) . " RESOURCE$brace}\n" }
    }
    if($line =~ /SERVICE_APPLICATION_EXECUTION_COMPONENT|WEB_APPLICATI
+ON_EXECUTION_COMPONENT|UNX|WNT/)
        { $$key = undef }
}
[download]