--- wp-includes/js/tinymce/tiny_mce.js.old	2006-05-28 22:27:41.000000000 +0530
+++ wp-includes/js/tinymce/tiny_mce.js	2006-05-28 22:27:34.000000000 +0530
@@ -5002,6 +5002,8 @@
 
 	// Remove end from absolute path
 	var len = baseURLParts.length-numBack;
+	if (len < 0)
+		len = 0;
 	var absPath = (len <= 0 ? "" : "/") + baseURLParts.slice(0, len).join('/') + "/" + relURLParts.join('/');
 	var start = "", end = "";