I am passing objects from one php script to anotherone 
using the session support. It seems to be working fine 
on Apache 1.3.6 with php4b3

Those same scripts in a Apache 1.3.12 with Php 4.0 dont work. In fact, no session suport is available.

A file is created in /tmp like this.
-rw-------   1 nobody   nogroup         9 Jun 26 01:31 sess_12bed2b02a7d0c1098ab1a9976cf79f1
with content:
!carrito|

instead of:
carrito|O:8:"stdClass":1:{s:5:"items";a:1:{i:10;i:3;}}
That shows the machine with the Php 4.0b3

The php.ini file is exactly alike from one machine to anotherone.

Any ideas why does this happen?