having a fatal error result with the php image upload code you uploaded. Please what should i do

having a fatal error result with the php image upload code you uploaded.
Please what should i do

This is the error report:
Fatal error: Using $this when not in object context in
C:\wamp\www\revfelixomobude.com\phpupload2.php on line 61
This is the code I used:
<?
// If Everything is good- process the form - write the data into the
database
$photo=$this->input->post('your_photo');
if($photo==NULL){$image_name='0';}// if no photo is selected the default
value of the photo would be 0
//photo upload starts
$errors=0;
if($_FILES['your_photo']){
$image=$_FILES['your_photo']['name'];
if($image) {
define ("MAX_SIZE","100");
function getExtension($str) {
$i = strrpos($str,".");
if (!$i) { return ""; }
$l = strlen($str) - $i;
$ext = substr($str,$i+1,$l);
return $ext; }
//reads the name of the file the user submitted for uploading
$image=$_FILES['your_photo']['name'];
//if it is not empty
if ($image)
{
//get the original name of the file from the clients machine
$filename = stripslashes($_FILES['your_photo']['name']);
//get the extension of the file in a lower case format
$extension = getExtension($filename);
$extension = strtolower($extension);
//if it is not a known extension, we will
suppose it is an error and will not
upload the file,
//otherwise we will do more tests
if (($extension != "jpg") && ($extension
!= "jpeg") && ($extension != "png") &&
($extension != "gif"))
{
//print error message
$msg="Sorry! Unknown extension. Please
JPG,JPEG,PNG and GIF only ";
$errors=1;
}
else
{
//get the size of the image in bytes
//$_FILES['image']['tmp_name'] is the
temporary filename of the file
//in which the uploaded file was stored on
the server
$size=filesize($_FILES['your_photo']['tmp_name']);
//compare the size with the maxim size we
defined and print error if bigger
if ($size < MAX_SIZE*1024)
{
//we will give an unique name, for example
the time in unix time format
$image_name=time().'.'.$extension;
//the new name will be containing the full
path where will be stored (images folder)
$newname="support/images/profile/".$image_name;
//we verify if the image has been
uploaded, and print error instead
$copied =
copy($_FILES['your_photo']['tmp_name'],
$newname);
if (!$copied)
{
$msg="Sorry, The Photo Upload was
unsuccessfull!";
$errors=1;
}
}
else
{
$msg="You Have Exceeded The Photo Size
Limit";
$errors=1;
}
}}}
/*Image upload process ends here- If any
problem occurs it will display error
message via the $msg,
otherwise it will upload the image to the
image folder. To insert the photo into
database $image_name has been used*/
}
if(($_FILES['your_photo'])&& ($errors))/* If any photo
is selected and any problem occurs while uploading it
will
display an
error
message,
otherwise
transfer
the data
to
Mod_addstudent
model */
{
echo $msg;
}
else {
//Insert into database.Just use this
particular variable "$image_name" when
you are inserting into database
$sql="INSERT INTO your_table
(field1, your_image_field) VALUES
('','$image_name')";
}
?>