log in function in ultradev

Please help me if you can
I am trying to use the built in function in ultra dev which allows you to have a login function. I have made a page called loginpage.htm which loads when the hyperlink to the desired protected page has been clicked. The login names and passwords are all stored in a database named login as well to verify the correct info. Once the username and password are filled in and the submit button is clicked the following page comes up as file not found when i have filled in the pages to go to and to redirect to if the login fails. The URL then ends up with a /<%MM_loginaction%> bit at the end of it.
You can try it if you like. The loginpage is at:
http://www.magnetic-solutions.co.uk/loginpage.htm
use username=guest
password=test
thanks for any help