Errore substr

[Dheed]

Non so bene quale sia il problema,ma funziona 'tutto' fino a quando non arrivo a $iden,questo è il codice(ho segnato dove c'è l'errore,è nelle prime righe):

<?php
include 'dbc.php';
page_protect();
    
$path=$_GET['path'];
if($path!='' && $path!='null' && $path!='undefined') {
        
    $site_name='http://farebury.exofire.net/';
    
    $path=str_replace($site_name,'',$path);
    $sept=str_replace('tree/','',$path);
    $leng=intval(stripos('/',$sept));
    $iden=substr($sept, 0 ,$leng); //errore
    $iden=trim($iden); //errore

    
    /*check if you can delete the folder*/
    $username=$_SESSION['user_nick'];
    $usid=$_SESSION['user_id'];
    
    $perm=$basepermfold.$usid.'/'.$username.'.txt';
    
    $var = implode('', file ($perm));
    $arrperm=explode("\n",$var);
    $permissiondelete=false;
    
    for($i=0;$i<count($arrperm);$i++){
        if($arrperm[$i]==$iden){
            $permissiondelete=true;
            break;
        }                
    }
    
    
    if($permissiondelete==true){
        /*Folder level*/
        $query="SELECT `folder_level` FROM `folder` WHERE `idd`='$iden'"; 
        $level=mysql_query($query,$link);
        
        $path=trim($path);
        $ceckph=str_replace('/','',$path);
        $ceckph=trim($ceckph);        
    
        $subfolder = '2' ;
        $mainfolder = '1' ;
    
        $permtxt = '/'.$username.'.txt';
    
        if($ceckph!='tree'){
            //elimino file
            if(is_file($path)==true){
                unlink($path);    
                echo "The file has been deleted";
            }
            //elimino cartella
        
            //sub folder
            else if(is_dir($path) && $level==$subfolder){
                $var = implode('', file ($read));
                $arr=explode("\n",$var);
            
                $check=delete_directory($path);
             
                if($check==true){
                
                    echo "The folder and his content has been deleted";         
                }                
                else
                    echo "There was a problem,couldn't delete the subfolder,please contact the Administrator"; 
            }
            //main folder
            else if(is_dir($path) && $level==$mainfolder){
                $read=$path.$infotxt;
                pulisci($read);
                $var = implode('', file ($read));
                $arr=explode("\n",$var);
                if(count($arr)==1){ //only one person
                    $check=delete_directory($path);             
                    if($check==true){
                        //delete permission
                        for($i=0;$i<count($arrperm);$i++){
                            if($arrperm[$i]==$iden){
                                $arrperm[$i]='';
                                break;
                            }                
                        }
                        $file = fopen($perm, "w+");
                        fwrite($file,$arrperm."\n");
                        fclose($file);
                        pulisci($perm);
                        $operation="DELETE FROM folder WHERE idd='$iden'";
                        mysql_query($operation,$link);
                        echo "The folder and his content has been deleted";         
                    }                
                    else
                        echo "There was a problem,couldn't delete the main folder,please contact the Administrator"; 
                }
                else{//more than one person
                    for($i=0;$i<count($arr);$i++){
                        if($arr[$i]==$username){
                            $arr[$i]='';
                            break;
                        }    
                    }                    
                    $file = fopen($read, "w+");
                    fwrite($file,$arr."\n");
                    fclose($file);
                    pulisci($read);
                
                    //delete permission
                    for($i=0;$i<count($arrperm);$i++){
                        if($arrperm[$i]==$iden){
                            $arrperm[$i]='';
                            break;
                        }                
                    }
                    $file = fopen($perm, "w+");
                    fwrite($file,$perm."\n");
                    fclose($file);
                    pulisci($perm);
                
                }
            }
        
            //no file or folder
            else {
                echo "There was a problem,couldn't identify the folder type,please contact the Administrator";
            }
        }
        else
            echo "You can't delete the Parent Folder.";

    }
    else
        echo "You can't delete this folder,because you don't own the permissions.";

}
function delete_directory($dirname) {
       if (is_dir($dirname))
          $dir_handle = opendir($dirname);
       if (!$dir_handle)
          return false;
       while($file = readdir($dir_handle)) {
          if ($file != "." && $file != "..") {
             if (!is_dir($dirname."/".$file))
                unlink($dirname."/".$file);
             else
                delete_directory($dirname.'/'.$file);    
          }
       }
       closedir($dir_handle);
       rmdir($dirname);
       return true;
    }
     

function pulisci($store){
$arr=array();
    foreach( file($store) as $line ){
            $line=trim($line);
        if($line != '') $arr[]=$line;
        }
    file_put_contents($store, implode("\n",$arr) );
}
?>

Qualcuno sa aiutarmi?