Okay. They reason you have a 404 on the front page is because you deleted the "Hello" or placeholder post. You need Staff intervention http://en.support.wordpress.com/contact/
Also we always require a link to the blog in question when you post to this forum. There are two choices (1) post it every time you post to this forum (2) link your username to the wordpress.com blog.
Here’s how to link your username to your blog in your blog Dashboard –> Users –> Your Profile. Then scroll down to where it says ‘Website‘ and fill in the address of your blog and then click ‘Update Profile‘.
Once you’re done click “Update Profile”. Voila! Now every time you sign into the forum we can all click on your username and your blog will be linked to it. And every time you leave a comment on a blog your username can be likewise clicked and your blog can be instantly located.
Note that there is a complete record of every post that you make to the forum on your forum profile page. Also note that when you mark a forum threads as “favorites” that you will find them listed on the forum profile page too. And everyone in the forum can access your forum profile by simply clicking on “Member” next to your username.