[Zope] Internal server error adding External Method

I'm trying to work through the giraffes example in Calling ZPT from Scripts in the online 2.6 Zope book. I created the file my_extensions.py in the Extensions directory and cut/pasted the Giraffes class code (preserving indentation). I then created a Giraffes folder and attempted to add the External Method named 'giraffes' as described in the docs. Every time I hit the Add button after filling in the External Method fields I get a "HTTP 500 - Internal server error" message. I'm using Zope 2.6.1 on WinME and the browser is IE6. Can anyone shed some light? I tried restarting Zope but get the same results. Thanks, Tom P. Allred, MCSE, RHCE, CCNA www.AllredData.com Tom@AllredData.com