need help Message: Undefined variable

PHP Code:

public function save(){
 $this->load->helper('date');
 if($_SERVER["REQUEST_METHOD"] == "POST"){
 $data = array(
 "USERNAME" => $this->input->post("email"),
 "PASSWORD" => md5($this->input->post("PASSWORD")),
 "CREATE_DATE" => NOW(),
 "STATUS" => 1,
 "USER_TYPE" =>2
 
 );
 $query = $this->db->insert("user", $data);
 if($query){
 $this->db->where("email", $this->input->post("email"));
 $q_profile = $this->db->query("SELECT id FROM user WHERE USERNAME ='{". mysql_real_escape_string($this->input->post('email')). "}' LIMIT 1");
 foreach ($q_profile->result() as $p){
 
 $uid = $p->id;
 
 }
 
 
 $profile = array(
 "USER_ID" =>$uid,
 "NAME" => $this->input->post("name"),
 "LASTNAME" => $this->input->post("lastname")
 );
 
 $query_profile = $this->db->insert("user_profile", $profile);
 if($query_profile){
 return true;
 }else{
 return false;
 }
 }
 
 }
 
 } 


A PHP Error was encountered

Severity: Notice

Message: Undefined variable: uid

Filename: models/model_register.php

Line Number: 31

Backtrace:

File: D:\AppServ\www\bilbo_ci\application\models\model_register.php
Line: 31
Function: _error_handler

File: D:\AppServ\www\bilbo_ci\application\controllers\page.php
Line: 47
Function: save

File: D:\AppServ\www\bilbo_ci\index.php
Line: 292
Function: require_once