diff --git a/XMPPHP/Roster.php b/XMPPHP/Roster.php
index 50f4023..30117bb 100644
--- a/XMPPHP/Roster.php
+++ b/XMPPHP/Roster.php
@@ -118,12 +118,13 @@ class Roster {
 	 * @param string $status
 	*/
 	public function setPresence($presence, $priority, $show, $status) {
-		list($jid, $resource) = explode('/', $presence, 2);
+		$presence = explode('/', $presence, 2);
+		$jid = $presence[0];
+		$resource = isset($presence[1]) ? $presence[1] : '';
 		if ($show != 'unavailable') {
 			if (!$this->isContact($jid)) {
 				$this->addContact($jid, 'not-in-roster');
 			}
-			$resource = $resource ? $resource : '';
 			$this->roster_array[$jid]['presence'][$resource] = array('priority' => $priority, 'show' => $show, 'status' => $status);
 		} else { //Nuke unavailable resources to save memory
 			unset($this->roster_array[$jid]['resource'][$resource]);