I am using this code to upload a file to my server. The code works in the sense that it is uploading the file successfully, including preventing uploads with wrong extensions .... however every time I upload a file I get the following error

Strict Standards: Only variables should be passed by reference in C:\upload.php on line 8

Below is my code, I have marked line 8. Any ideas??? Thanks in advance

Code PHP:
$message = '';
$target_path = "C:\mypathhere";
$target_path = $target_path . basename( $_FILES['uploadedfile']['name']); 
$file = $_FILES['uploadedfile']['name'];
$allowed_ext = array('csv','txt','rtf');
$actualext = end(explode(".", $file)); // Line 8
	if( $file > 1111111){ 
			$message = 'File over 1111111 bytes';
		} if ($message == NULL && !in_array($actualext, $allowed_ext)){ 
			$message = 'File extension not allowed';
		} if($message == NULL){
			if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
				echo "The file ".  basename($file)." has been uploaded";
			} else{
				echo "There was an error uploading the file, please try again!";
echo $message;