Index: trackback/files/lib/util/TrackbackUtil.class.php
===================================================================
--- trackback/files/lib/util/TrackbackUtil.class.php (revision 136)
+++ trackback/files/lib/util/TrackbackUtil.class.php (revision 137)
@@ -12,5 +12,6 @@
  */
 class TrackbackUtil {
-	protected $agent = 'Woltlab Burning Board Trackback Mod';
+	protected static $agent = 'Woltlab Burning Board Trackback Mod';
+	protected static $timeout_bytes = 51200;
 
 	/**
@@ -127,5 +128,6 @@
 		// merge pingbacks with public pingback services
 		$pingbacks = array_merge($pingbacks, explode("\n", StringUtil::unifyNewlines(MESSAGE_PINGBACK)));
-
+		$pingbacks = array_filter($pingbacks, create_function('$a','return !empty($a);'));
+		
 		// send pingbacks
 		foreach($pingbacks as $pingbackurl) {
@@ -243,5 +245,5 @@
 			}
 			$byte_count += strlen($line);
-			if ( $byte_count > $timeout_bytes ) {
+			if ( $byte_count > self::$timeout_bytes ) {
 				// It's no use going further, there probably isn't any pingback
 				// server to find in this file. (Prevents loading large files.)