There is only one main page for posts in a blog and all posts will display on the main blog page. There is no way to exclude posts from the main posts (blog) page.
The front page of the blog by default will display your posts (not pages) in reverse chronological order, with the most recently published post on top. If you do not want all the posts to show on the front page, then you can create a static front page “Welcome” for your site and a “Blog” page for posts.
Choice 1 static front page
Choice 2 running page for all posts on front page
Which do you choose? It’s one or the other. If you choose a static front page then you have to create two pages as I said above. After you do that you go to > Settings > Reading and make the designation change and click “save changes”. http://en.support.wordpress.com/pages/front-page/
If you set a static front page and fail to create a page for blogs to appear on and designate it here > Settings > Reading then that coul be the cause of your issue.