[Seaside] Seaside debugger not coming up on error, pleas help

[fritz schenk]

I am running Pharo1.0 with Seaside 3.0a.

I am unable to locate options in the configuration of of the application for the
exception filter.

I see that 'Exception Handler	WAHtmlErrorHandler' followed by 'Override' button,
nothing else.

The code issuing an error is accessible in http://www.pastebin.org/259965
(available for the next month)

The error issued and viewable in the browser is #
"MessageNotUnderstood: receiver of "contents" is nil

Your request could not be completed. An exception occurred."

There is no indication in the IDE that error has occurred, and no link

Thank for help