Mr.kows, the first problem dosn't solved
still some rar files downloaded corruptly through script, while correctly through direct downloading.

I really tired with this code. It taked alot of time

Here is the full code with intending:
Code:
<? ob_start(); ?>
<?php
	session_start();
	echo '<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >';
	error_reporting(0);
	if(trim($_SESSION['downloadid'])=="" or (isset($_SESSION['downloadid'])==false)) {
		echo "You Can't access this page directly";
		exit;
	}
	include("dbconnect.php");
	$fileid=(int) $_SESSION['downloadid'];
	$_SESSION['downloadid']="";
	$mysqlresult=mysql_query("select * from file where id=".$fileid) or die("Error");
	$rnum = mysql_num_rows($mysqlresult);
	if($rnum<=0) {
		echo "File Dosn't Exists";
		exit;	
	}
	$fname = mysql_result($mysqlresult,0,'fname');
	$ftitle = mysql_result($mysqlresult,0,'ftitle');
	$fsize = mysql_result($mysqlresult,0,'fsize');
	$ftype = mysql_result($mysqlresult,0,'ftype');

	$filename="./SAVEDFILES/".$fname;
	// addition by Jorg Weske
	$file_extension = strtolower(substr(strrchr($filename,"."),1));

	if ( ! file_exists( $filename ) ){
  		echo "<html><title>Error</title><body>Error: File Dosn't Exists</body></html>";
  		exit;
	}
	$bbb = basename($filename);
	$nnn = substr($bbb,0,strpos($bbb,'.'));
	$filetts = substr($bbb,strpos($bbb,'.'));
	$ffffff = $nnn;

//=======================================================
	function output_file($file, $name, $mime_type=''){
		if(!is_readable($file)) die('File not found or inaccessible!');
		$size = filesize($file);
		$name = rawurldecode($name);

		$known_mime_types=array(
		"pdf" => "application/pdf",
		"txt" => "text/plain",
		"html" => "text/html",
		"htm" => "text/html",
		"exe" => "application/octet-stream",
		"zip" => "application/zip",
		"doc" => "application/msword",
		"xls" => "application/vnd.ms-excel",
		"ppt" => "application/vnd.ms-powerpoint",
		"gif" => "image/gif",
		"png" => "image/png",
		"jpeg"=> "image/jpg",
		"jpg" => "image/jpg",
		"php" => "text/plain"
		);

		if($mime_type==''){
			$file_extension = strtolower(substr(strrchr($file,"."),1));
			if(array_key_exists($file_extension, $known_mime_types)){
				$mime_type=$known_mime_types[$file_extension];
			}else{
				$mime_type="application/force-download";
			}
		}

		@ob_end_clean(); //turn off output buffering to decrease cpu usage

	// required for IE, otherwise Content-Disposition may be ignored
		if(ini_get('zlib.output_compression')) ini_set('zlib.output_compression', 'Off');

		header('Content-Type: ' . $mime_type);
		header('Content-Disposition: attachment; filename="'.$name.'"');
		header("Content-Transfer-Encoding: binary");
		header('Accept-Ranges: bytes');

		header("Cache-control: private");
		header('Pragma: private');
		header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

// multipart-download and download resuming support
		if(isset($_SERVER['HTTP_RANGE'])){
			list($a, $range) = explode("=",$_SERVER['HTTP_RANGE'],2);
			list($range) = explode(",",$range,2);
			list($range, $range_end) = explode("-", $range);
			$range=intval($range);
			if(!$range_end) {
				$range_end=$size-1;
			} else {
				$range_end=intval($range_end);
			}

			$new_length = $range_end-$range+1;
			header("HTTP/1.1 206 Partial Content");
			header("Content-Length: $new_length");
			header("Content-Range: bytes $range-$range_end/$size");
		} else {
			$new_length=$size;
			header("Content-Length: ".$size);
		}


		$chunksize = 1*(10*10); //you may want to change this
		$bytes_send = 0;
		if ($file = fopen($file, "rb")){
			if(isset($_SERVER['HTTP_RANGE'])) fseek($file, $range);

			while(!feof($file) && (!connection_aborted()) && ($bytes_send<$new_length)){
				$buffer = fread($file, $chunksize);
				print($buffer); //echo($buffer); // is also possible
				flush();
				$bytes_send += strlen($buffer);
			}
			fclose($file);
		} else die('Error - can not open file.');
	} 

	set_time_limit(0); 
	$file_path=$filename;
	output_file($file_path, $ftitle);
?>
<?php ob_flush(); ?>