fix null exception

Author: Gargaj

include_pouet/request-classes.inc.php

@@ -904,6 +904,11 @@ static function Display($itemID, $data)
     for ($x=1; $x<=96; $x++) $ranks[$x] = $x;
 
     $prod = PouetProd::Spawn( $itemID );
+    if (!$prod)
+    {
+      printf("prod %d missing.");
+      exit();
+    }
     $a = array(&$prod);
     PouetCollectPlatforms( $a );