Upload Script help

[red_bull_NRG]

I'm very new to php and I'm working on an upload script. I want it to assign the uploaded file a random name and then save it in a specific directory on the server. For some reason when this code is executed it says that the file already exists. What is causing this?

Here's the code:

<?php

$name = rand(100, 10000000000000);

if (($_FILES["file"]["size"] < 2000000000))
  {
  if ($_FILES["file"]["error"] > 0)
    {
	echo "Error:  " . $_FILES["file"]["error"] . "<br/>";
	}
  else
    {
	echo "Upload:  " . $_FILES["file"]['$name'] . "<br/>";
	echo "Type:  " . $_FILES["file"]["type"] . "<br/>";
	echo "Size:  " . ($_FILES["file"]["size"] / 1024) . " KB<br/>";
	echo "Stored in:  " . $_FILES["file"]['$name'];
	}
  if (file_exists("upload/" . $_FILES["file"]['$name']))
      {
      echo $_FILES["file"]['$name'] . " already exists. ";
      }
      else
      {
      move_uploaded_file($_FILES["file"]["tmp_name"],
      "upload/" . $_FILES["file"]['$name']);
      echo "Stored in: " . "upload/" . $_FILES["file"]['$name'];
      }
    }	
else
  {
  echo "Invalid file";
  }
?>