I can't create post from the front-end area

Only users with suffiecient group permissions can add a new post from the front-end. If your group does not have the Can submit articles option set to Yes, then you will not be able to add a new post. Another option that can restrict this functionality is the Enable moderation option, if this option is enabled then your blog post will need to be manually approved by an administrator before it will be published. You can edit these permissions by going to Components > RSBlog! > Groups.

You can read more about group permissions here.