求救，我真的不知道是什么错误了!!!!!!!!!!!!!

string strSql="Insert into UserInfo(UserName,UserSex,UserPwd,UserBirthday,PwdQuestion,PwdAnswer,UserEmail,RegDate,LastLoginDate) Values('"
            +txtName.Text.Trim()+"','"
            +radiosex.SelectedItem.Value+"','"
            +dtBirthday+"','"
            +txtPwd1.Text.Trim()+"','"
            +txtQuestion.Text.Trim()+"','"
            +txtAnswer.Text.Trim()+"','"
            +txtEmail.Text.Trim()+"','"
            +DateTime.Now.ToLongDateString()+"','"
            +DateTime.Now.ToLongDateString()+"')";  
    Response.Write(dtBirthday);
    OleDbCommand objCmd=new OleDbCommand(strSql,objConn);
    objCmd.Connection.Open();
    objCmd.ExecuteNonQuery();
    objConn.Close();
    Response.Redirect("Login.aspx");