I have a great problem with sessions, can anybody help me!!!

I install a new system RH6.2 width some updates the kernel is a 2.2.17-14 I use Apache 3.1.14 whit PHP 4.0.4pl1 compiles as a module. I use a test page that is very simple to check sessions: <?php session_start(); if( !isset( $c)) { session_register("c"); $c = 1; } echo $c . "<br>"; ?> <a href="index.php">reload</A> In the new machine this code every show 1, don't save session data. I see in /tmp and all the sess_* files are empty. I check configuration, etc, and don't found anything. I check the same code in other machine with the same configuration, and works fine. Can anybody help me??