PHP: Old file upload class

class d_upload {

	var $formfields;
	var $errorback;
	var $whichfields;
	var $sendfieldinfoback;

	var $ads_upload_dir = "../pdfs/";
	var $ads_upload_max_filesize = 10240000;


  ##########
	function upload_add_ad($thefiletoupload,$upload_filesize,$upload_file_type,$temp_file_upload_name,$file_upload_error){
		
		$uploadDir = $this->ads_upload_dir.$_POST['event']."/";

		if ($file_upload_error != 0){
			if ($file_upload_error == 1){
				$this->errorback = 1;
				$this->whichfields .= "filesize,";
			}
			if ($file_upload_error == 2){
				$this->errorback = 1;
				$this->whichfields .= "filesize,";
			}
			if ($file_upload_error == 3){
				$this->errorback = 1;
				$this->whichfields .= "partialupload,";
			}
			if ($file_upload_error == 4){
				$this->errorback = 1;
				$this->whichfields .= "nofileuploaded,";
			}
		} else {
		
			if ($upload_filesize == 0 || $upload_filesize > $this->ads_upload_max_filesize){
				$this->errorback = 1;
				$this->whichfields .= "filesize,";
				
			}
			if (! preg_match("/^application\/x-msdownload|application\/pdf$/i",$upload_file_type)){
				$this->errorback = 1;
				$this->whichfields .= "wrongformat,";
			}
			
		}	
		
		
    $firstfilebit = preg_replace("/^(.+)\.pdf$/i","\\1",$thefiletoupload);

	$knockout = array("~", "`", "!", "@", "#", "$", "%", "^", "&", "*");
	$newname = str_replace($knockout, "_", $firstfilebit);
	$newname = preg_replace("/_{2,}/","_",$newname);

		
		
	$newfilename = $newname.".pdf";
	
		
		
		
		
		
			
		if (! $this->errorback){
			$newrandomfilenamewithpath = $uploadDir . $newfilename;
			@move_uploaded_file($temp_file_upload_name, $newrandomfilenamewithpath);
			@chmod($newrandomfilenamewithpath, 0644);
		}
		
		
		if ($this->errorback){
			$this->whichfields = substr($this->whichfields, 0, -1);
			header("Location: ../?err=uploadfileproblem&whichfields=$this->whichfields");
			exit;
		} else {
			//## everything OK
			// back to file
		}
	} // end fucnction upload_add_ad
	
	
	
	##########

} // end class