58582 site script error

I have a site that is showing some errors is using (global variables) and this is causing us not to be able to log into the admin and basically the scipt is not working. we must make the scrit not use global variables but use "season variables". this is the error its showing : 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. Site url is [login to view URL] .