fix entries not inserted properly when no languages are detected

include/rssfuncs.php

@@ -577,6 +577,8 @@
 					$entry_language = db_escape_string(substr($entry_language[0], 0, 2));
 
 					_debug("detected language: $entry_language", $debug_enabled);
+				} else{
+					$entry_language = "";
 				}
 
 				$entry_comments = $item->get_comments_url();