dont try to use something that isn't there

files/ajax/scan.php

@@ -22,6 +22,10 @@ if($force or !OC_FileCache::inCache('')){
 		exit;
 	}
 }else{
-	$eventSource->send('success',false);
+	if(isset($eventSource)){
+		$eventSource->send('success',false);
+	}else{
+		exit;
+	}
 }
 $eventSource->close();

lib/filecache.php

@@ -325,7 +325,9 @@ class OC_FileCache{
 						$mimetype=OC_Filesystem::getMimeType($file);
 						$stat['mimetype']=$mimetype;
 						self::put($file,$stat);
-						$eventSource->send('scanned',$file);
+						if($eventSource){
+							$eventSource->send('scanned',$file);
+						}
 						$totalSize+=$stat['size'];
 					}
 				}