Go through the Seam tutorials and documentation.
My initial thoughts are that you have not setup your web.xml properly.
When working with Seam it is important that you spend a good amount of time reading the doco and looking at the examples. It may seem like time wasting because you are not working on your own project but, if you do not do this then you will be spending a LOT of time waiting for someone to come answer your questions on the forum.
Remember people will be more likely to spend time answering your problems if you have spent the time researching and reading yourself first.
When ever you have problems you should always go read the server logs. And you should always provide as much relevant information as possible.
Did Seam even boot up?
Do you have any other pages that you can access that use Seam?
Have you mapped .seam properly in your web.xml?
Are there any exceptions in your server logs?
Have you setup logging so you can see the log messages coming from the Seam lib so that you can tell if Seam is complaining about something?
If you cannot answer any of these questions it means you need to go back to the doco and examples.