File Upload working on PHP4 but not PHP5
===

I have an application designed in a local install (PHP4/MySQL) and it works perfectly. Since I moved it to a live install (PHP5/MySQL) I have had nothing but issues! I fixed any global variable issues (lead me to learn PDOs so not a bad thing!) without turning global variables on, so the only issue I have is with file uploads. I tried an isset test for $_file and it looks like the variable was never set? Any ideas? 

Here is the form data: 

         <form enctype="multipart/form-data" method="post" action="script_add_product.php" >   
					
         <input class="cp_forms_upload" type="file" name="full_image" />
						 
         <input class="cp_formsButton" type="submit" name="submit_button" value="Add Product" /></form>



And here is the PHP: 

        $full_image_url = $_FILES["full_image"]["name"];	 
		 
        if ((($_FILES["full_image"]["type"] == "image/gif")
        || ($_FILES["full_image"]["type"] == "image/jpeg")
        || ($_FILES["full_image"]["type"] == "image/pjpeg")
        || ($_FILES["full_image"]["type"] == "image/png"))
        && ($_FILES["full_image"]["size"] < 400000))
          {
         if ($_FILES["full_image"]["error"] > 0)
          {
           echo "Return Code: " . $_FILES["full_image"]["error"] . "<br />";
           }
         else
           {
          echo "Upload: " . $_FILES["full_image"]["name"] . "<br />";
          echo "Type: " . $_FILES["full_image"]["type"] . "<br />";
          echo "Size: " . ($_FILES["full_image"]["size"] / 1024) . " Kb<br />";
          echo "Temp file: " . $_FILES["full_image"]["tmp_name"] . "<br />"; 

          if (file_exists("../Uploads/" . $_FILES["full_image"]["name"]))
           {
             echo $_FILES["full_image"]["name"] . " already exists. ";
            } 
          else 
             {
             move_uploaded_file($_FILES["full_image"]["tmp_name"],
             "../Uploads/" . $_FILES["full_image"]["name"]);
             echo "Stored in: " . "../Uploads/" . $_FILES["full_image"]["name"];
	     echo "<br /><br /><br />" . $full_image_url;
             }
           }
	
          }
  
          else
          {
         echo "Invalid file";
           }

Thanks folks :)