Cannot update profile in edit page

Hi,
I created a "register.aspx" page and allow user to register their username and profile, everything is fine, I have created "editprofile.aspx" page and allow user to update their profile, the edit page can load the profile history, but it cannot update to profile!
I don't know what is going on, please help! Many thanks.
 
below is my code:
register.aspx.cs      ***<this part updated sucessfully>****

1 protected void StepNextButton_Click(object sender, EventArgs e)
2 {
3 Session["seslogin"] = User.Identity.Name;
4 MultiView1.ActiveViewIndex = 1;
5 }
6 protected void v2btnsubmit_Click( ...