GNU Emacs 23.2.1 (x86_64-apple-darwin10.4.0, NS apple-appkit-1038.32) of 2010-08-27 on ishida-souichi-no-MacBook.local

I get an error,

Wrong type argument: characterp, sgml-xml-mode

when implementing org-googlecl.el .  It seems like this particular is not the cause of the error above.
How can I trace the cause of errors?

If anyone has a resolution to it, I would appreciate it.


Regards, 

soichi