Index: /CKEditor/branches/versions/3.6.x/_source/plugins/enterkey/plugin.js
===================================================================
--- /CKEditor/branches/versions/3.6.x/_source/plugins/enterkey/plugin.js	(revision 6818)
+++ /CKEditor/branches/versions/3.6.x/_source/plugins/enterkey/plugin.js	(revision 6819)
@@ -59,5 +59,5 @@
 			}
 			// Don't split <pre> if we're in the middle of it, act as shift enter key.
-			else if ( !atBlockEnd && block.is( 'pre' ) )
+			else if ( !atBlockEnd && block && block.is( 'pre' ) )
 				return enterBr( editor, mode, range, forceMode );