Permalink problems!

Hello,
I’ve been making a contact form on my little site today, and have been very frustrated by an annoying yet seemingly quite simple problem.

<form class="contactform" action="" method="post" name="contact_form">

is the action of the contact form, the page url is:
http://cssrecycling.co.uk/stage/contact-css-recycling/
however when you press submit it takes you to the page:
http://cssrecycling.co.uk/stage/stage/contact-css-recycling/
and you get a 404.

I have treid:
hardcoding the url: (it inserts the extra ‘/stage/’ still
using a different page: still inserts an extra /stage/ in the url

and I’m totally confused as to ehat its doing, the rest of the site links work fine it’s only when I sue the <form action=””> that the url gets messed up!

Am using post name permalinks and the blog lives in the /stage/ folder.
Any advice is appreciated!