[PHP] Session side effect warning

I've written a php appication and linked it inside a Joomla1.5 site.
My application needs to write some variables into the session, but at the bottom of the page I get this message
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

Those settings are written inside php.ini file, but I have no access to it.
Is there any other way to hide that message?
I'm a php newbie, so I could say a wrong thing, but I was thinking to something like this: is there a way to say to the page "if you receive a text with this words don't write it, throw it away"?
If it is not possible, how could I solve my problem?

Solved using error_reporting(0) inside the page.