use HTTP::Request;
	use LWP::UserAgent;
	my $url = "http://".$PREF{webServer}."/index.php?act=upload&task=checkMd5&md5=".$md5."&id=".$PREF{uploadid};
	my $ua = LWP::UserAgent->new;
	my $req = new HTTP::Request(GET => $url);
	my $resp = $ua->request($req);
	my $result = $resp->content();
	if ($result eq 'wrong' ) 
	{
		unlock_log_file();
		fatal_error( "不能重复上传同一个文件" );
	}