Index: src/includes/core/capabilities.php
===================================================================
--- src/includes/core/capabilities.php	(revision 7250)
+++ src/includes/core/capabilities.php	(working copy)
@@ -285,6 +285,10 @@
  */
 function bbp_add_forums_roles( $wp_roles = null ) {
 
+	if ( null === $wp_roles ) {
+		$wp_roles = new stdClass();
+	}
+
 	// Get the dynamic roles
 	$bbp_roles = bbp_get_dynamic_roles();