allora volevo trovare l'altezza di un immagine
uploadata ma mi da sempre questi errori

Warning: imagecreatefromjpeg() [function.imagecreatefromjpeg]: Unable to access cars team.png in /membri/imageblast/cutenews/upload-immi/Upload.php on line 49

Warning: imagecreatefromjpeg(cars team.png) [function.imagecreatefromjpeg]: failed to open stream: No such file or directory in /membri/imageblast/cutenews/upload-immi/Upload.php on line 49

Warning: imagesx(): supplied argument is not a valid Image resource in /membri/imageblast/cutenews/upload-immi/Upload.php on line 50

Warning: imagesy(): supplied argument is not a valid Image resource in /membri/imageblast/cutenews/upload-immi/Upload.php on line 51
e questo e lo script
che cosa sbaglio???
Codice PHP:
<div align=cenetr><img src=http://imageblast.altervista.org/thedownload/upload.png>
<style type="text/css">
p.none {border-style:none}
p.dotted {border-style:dotted}
p.dashed {border-style:dashed}
p.solid {border-style:solid}
p.double {border-style:double}
p.groove {border-style:groove}
p.ridge {border-style:ridge}
p.inset {border-style:inset}
p.outset {border-style:outset}
p.hidden {border-style:hidden}
</style>

<script src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php/it_IT" type="text/javascript"></script><script type="text/javascript">FB.init("ddf432c7246130f113042d22eaf2b71f");</script>+
<?php
include ("config.php");
//Funzioni utili...
//Funzione Replace " " in "_" (evitiamo possibili errori)
function fSpace($string)
{
    return 
str_replace(" ""_"$string);
}

//Funzione per ricavare l' estensione di un File
function fExt($string)

    
//Controllo il file
    
$trova_punto explode("."$string);
    
$estensione $trova_punto[count($trova_punto) - 1];
    
$estensione strtolower($estensione);
    
    
// Se non ci sono estensioni
    
if (isset($trova_punto[1]) == FALSE)
    {
        return 
'';
    }
    
//Ritorno il valore dell' estensione
    
return $estensione;
}
//Effettuo l' upload dell' immagine...
$ip $_SERVER['REMOTE_ADDR'];
$ora = (date("G:i"));
$data = (date("d-m-y"));
$est fExt($uploadfile);
$uploaddir '../_altervista_ht/';
$uploadfile fspace($_FILES['txt_file']['name']);
$nome rand().$ip.$ora.$data;
$upload $uploaddir $nome.$uploadfile;
$img imagecreatefromjpeg($_FILES['txt_file']['name']); 
$width imagesx($img); 
$height imagesy($img);
$url "http://imageblast.altervista.org/cutenews/$upload";
$name $nome.$uploadfile;



//Controllo che sia stato specificato un file
if(!strlen($uploadfile) == 0)
{
    
//Controllo l' estensione del file
    
if((fExt($uploadfile) == 'gif') or (fExt($uploadfile) == 'jpeg') or (fExt($uploadfile) == 'png') or (fExt($uploadfile) == 'jpg') or (fExt($uploadfile) == 'JPG') or (fExt($uploadfile) == 'pbm') or (fExt($uploadfile) == 'bmp') or (fExt($uploadfile) == 'ico'))
    {
        
             
//Eseguo l' upload
        
if(move_uploaded_file($_FILES['txt_file']['tmp_name'], $upload))
        {
          
$query "INSERT INTO  imageuplaod (id, name, url, height, width) VALUES ('','$name','$url','$height','$width')";
          
mysql_query($query) or die(mysql_error());
            
//Upload eseguito con successo
            
                        
echo "-----Upload eseguito correttamente-----<fb:share-button class='url' href='http://imageblast.altervista.org/cutenews//$upload' type='box_count'></fb:share-button>";
            echo 
"<p class=outset align=center>
[img]"
$upload ."[/img]

</p>"
;
            echo 
"

[url='imageblast.php?do=upload']Carica una nuova immagine[/url]

"
;
                        echo 
"
<div align='right'><fb:share-button class='url' href='http://imageblast.altervista.org/cutenews/
$upload' type='box_count'></fb:share-button>
</div>"
;
                        echo 
"
Links all'immagine:"
;
                        echo 
"
<input type=url class=classetd onclick=s(this); size=100 value=http://imageblast.altervista.org/cutenews/
$upload></input></td>

"
;
                        echo 
"
Codice Forum:"
;
                        echo 
"
<input type=url class=classetd onclick=s(this) size=100 value=[url=http://imageblast.altervista.org][img]http://imageblast.altervista.org/cutenews/
$upload[/img][/url]></input></td>

"
;
                        echo 
"
Codice per Siti Web:"
;
                        echo 
"
<input type=url class=classetd onclick=s(this) size=100 value='[url="
http://imageblast.altervista.org/><img"][/url]'></input></td>

";
        }else{
            //Upload fallito
            echo "
Upload fallito !
";
        }
    }else{
        //Messaggio di errore
        echo "
File non valido";
        echo "
[url='imageblast.php?do=upload']Torna dietro[/url]
";
                echo "
[url='imageblast.php?do=upload'][img]http://imageblast.altervista.org/cutenews/error.png[/img][/url]
";
    }
}else{
    //Messaggio di errore
    echo "
Specificare un file !";
    echo "
[url='imageblast.php?do=upload']Torna dietro[/url]
";
        echo "
[url='imageblast.php?do=upload'][img]http://imageblast.altervista.org/cutenews/errore1.png[/img][/url]
";
}
?>