I'm having real trouble with cascading combo boxes on an Access form. Can anyone help?

I've setup a database to help with my football betting for next season and I'm trying to filter three subforms using two combo boxes, populated by season and division. I can get one combo box working perfectly, for season, but getting two working together is currently driving me nuts.

If there's anyone with sufficient Access/SQL/VBA knowledge to put me right I'd be very grateful. I can zip up the db and email you it and explain in more detail what I'm trying to do.

Thanks.