There was an old thread with this same subject:
http://groups.google.com/group/microsoft.public.dotnet.framework.interop/browse_
thread/thread/a6f451e1677943c3/06fafc27f869273e?q=mshtml+htmlformelement+events&
rnum=1#06fafc27f869273e

Which addressed mshtml's inability to bind to a form's OnSubmit event -
it freezes the entire form / page when you bind to this event, then try
and execute.

There are no errors, error messages, or exceptions to be seen. All
other events seem to work fine except this one suggesting a bug.

Please review the above thread - I've done all the same operations. The
reason why you can't just bind to the submitting "button" (which I've
done successfully) is because some forms run validation code which then
executes the javascript <form>.submit(); call which you won't catch if
you are just catching the button click.

Thank you.