diff --git a/library/Erfurt/Syntax/RdfParser/Adapter/RdfXml.php b/library/Erfurt/Syntax/RdfParser/Adapter/RdfXml.php
index 4f12422d..0d28d26e 100644
--- a/library/Erfurt/Syntax/RdfParser/Adapter/RdfXml.php
+++ b/library/Erfurt/Syntax/RdfParser/Adapter/RdfXml.php
@@ -202,7 +202,7 @@ protected function _startElement($parser, $name, $attrs)
         }
         
         $idx = xml_get_current_byte_index($parser) - $this->_offset*4096;
-        if (($idx >= 0) && ($this->_data[$idx].$this->_data[$idx+1]) === '/>') {
+        if (($idx >= 0) && (strlen($this->_data) > ($idx+1)) && ($this->_data[$idx].$this->_data[$idx+1]) === '/>') {
             $this->_currentElementIsEmpty = true;
         } else {
             $this->_currentElementIsEmpty = false;