为什么open老是出错？

ningbo

#!/usr/bin/perl

$configurl = "/var/www/";

$config_file = "router.cfg";
$config_file2 = "router2.cfg";
print "Content-type:text/html\n\n";
use CGI;
$req = new CGI;
$lan_ip = $req->param("lan_ip");
               
open(CONFIG,"<$configurl$config_file");


//这里，打开些文件老是出错，会是什么原因？
if(!(open (OUTFILE, ">$configurl$config_file2")))
{
        print "Failed";
        }
@array = <CONFIG>;
foreach $var(@array)
{
        if($var =~ m/LAN_IP/)
        {
        ($name,$value) = split(/=/,$var);
        print OUTFILE "$name=$lan_ip";
        next;
        }       
print OUTFILE $var;
}
close(OUTFILE);
close(CONFIG);       


unlink("$configurl$config_file");
rename("$configurl$config_file2","$configurl$config_file");