[PHP] Newbie

[Ilyas]

Hi all

I downloaded the oscommerce online shop. I have no experience with php. I 
installed yesterday php 4.3.

Just my question: I get this error if I call the startpage of this shop:

Warning: Unknown(): Your script possibly relies on a session side-effect 
which existed until PHP 4.2.3. Please be advised that the session extension 
does not consider global variables as a source of data, unless 
register_globals is enabled. You can disable this functionality and this 
warning by setting session.bug_compat_42 or session.bug_compat_warn to off, 
respectively. in Unknown on line 0

Thanks for any information

Ilyas