Index: _source/core/ckeditor_base.js
===================================================================
--- _source/core/ckeditor_base.js	(revision 4858)
+++ _source/core/ckeditor_base.js	Mon Mar 22 23:02:57 CST 2010
@@ -136,6 +136,9 @@
 						path = location.href.match( /^[^\?]*\/(?:)/ )[0] + path;
 				}
 
+				if( !path )
+						throw '[CKEDITOR] Installation path not found, please set the global variable "CKEDITOR_BASEPATH" before creating editor instances.';
+
 				return path;
 			})(),