Workflows not firing

[hodge]

I have some simple workflows set to fire when items are changed or
created. Everything fires and the logic works when I MANUALLY update
the records. However, I want to use some custom event handler code to
update the tables. When that update occurs (via the event handler)
the work flows do NOT fire. Why?

I'm using the designer (sp 2007) to create the workflows. Again
everything works exactly how I want when I change the lists myself
(meaning from the web page).

Thanks for any help.
adam