Basic facebook web application session info is missing

I made really basic facebook application, which collect permission from user to post data. Some time ago (around New year) it worked fine. I am using http://facebooktool开发者_高级运维kit.codeplex.com, and my code looks like this:

public partial class Facebook : CanvasFBMLBasePage
{
   protected void Page_Load(object sender, EventArgs e)
   {
      if(this.Api.Users.HasAppPermission(global::Facebook.Schema.Enums.ExtendedPermissions.publish_stream))

And at this moment I am having exception: parameter uid or session key required

As i understand, I should have some session defined by Facebook and CanvasFBMLBasePage should parse it, and make it possible to use application, but this is not happening.

My application settings (maybe I mis something):

• Canvas Callback URL: http://www.domain.com/app/action/facebook.aspx?
• Render Method: FBML
• Also, I put my IP in server whitelist.

Thanks for help

Have you called the "ConnectToFacebook" method in the api before calling "HasAppPermission"?