Filters not being applied

I have just installed Typo by pulling down the trunk out of svn. I have
attempted to create a page using the Markdown filter. Everything looks
fine
in the preview window during page construction but when I save the page
all
I get is the markup, not the rendered display, its like the filter isn’t
being applied.

Am I missing a step? Do I need to enable the default filters so that my
text is rendered correctly? Why does it look fine in preview but not in
the
final display.

Thanks!

Josh