Submit button not working as intended

I don't understand what stop triggering insert procedure for the below configuration while on a separate test page works perfectly. I have a tab which get active based on code behind control.

    
    
    

    


        

            Echipament
        

    

Then on Echipament tab

On code behind

protected void AddEchipament(Object sender, EventArgs e)
{
    if (Session["AID"] != null)
    {
        int aid = Int32.Parse(Session["AID"].ToString());
        using (SqlConnection conn = new SqlConnection(connString))
        {
            using (SqlCommand cmd = new SqlCommand("AddActivitateEchipament", conn))
            {
                cmd.CommandType = CommandType.StoredProcedure;

                cmd.Parameters.AddWithValue("@Echipament", txtEchipament.Text);
                cmd.Parameters.AddWithValue("@AID", aid);
                conn.Open();

                int result = cmd.ExecuteNonQuery();
                if (result > 0)
                {
                    ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "alertMessage", "alert('Record Inserted Successfully')", true);
                }

                conn.Close();

                txtEchipament.Text = string.Empty;
                ActiveTAB.Value = "#TabEchipament";
            }
        }
    }
}

Whitout the tab setup is working, with is not but I can't figure out why? Please help