Update problem

Hello, I have a php update form which use $_POST and $_GET too. I call the update like this update.php?id=1 And after the user submit the form with new data I use command like this: UPDATE table SET id=$_POST['id'] WHERE $_GET['id']='1'; This code works on localhost with Apache 2, Win XP, and Php 4.3.5 but it doesn't works on my real server(Php 4.3.3, Linux, Apache 1.??) I debuged it and I realised that on localhost I have the correct value in the $_GET but in remote $_GET is empty. What can I do? Thanks!