PHP - cargar archivo pdf con php

al momento de hacer click en el boton de enviar me aparcece que si quiero abrir el php y no me guarda el documento que envie
me podrian decir que esta mal en el codigo o por que hace eso???????

el codigo es el siguiente:

<form enctype="multipart/form-data" action="uploader.php" method="post">
<input type="hidden" name="MAX_FILE_SIZE" value="100000" />
Choose a file to upload: <input name ="uploadedfile" type="file" /> <br />
<input type="submit" value="Upload File"/>
</form>

<?php
// Where the file is going to be placed
$target_path = "uploads/";

/* Add the original filename to our target path.
Result is "uploads/filename.extension" */
$target_path = $target_path . basename( $_FILES['uploadedfile']['name']);

$target_path = "uploads/";

$target_path = $target_path . basename( $_FILES['uploadedfile']['name']);

if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
echo "The file ". basename( $_FILES['uploadedfile']['name']).
" has been uploaded";
} else{
echo "There was an error uploading the file, please try again!";
}

?>