Index: includes/purl_path.inc
===================================================================
--- includes/purl_path.inc	(revision 561)
+++ includes/purl_path.inc	(working copy)
@@ -83,7 +83,7 @@
     $alt = $this->remove($path, $element);
 
     if ($alt == $path && !_purl_skip($element, $options, $path)) {
-      $items = explode('/', $path);
+      $items = (empty($path) ? array() : explode('/', $path));
       array_unshift($items, $element->value);
       $path = implode('/', $items);
     }