When Session encounters an error, it calls die().  You will probably want to wrap your session logic in an eval block to trap these errors.

##</code><code>##

eval {
 tie %session, 'Apache::Session::File', $session_cookie,
    {
        Directory       => "../data/sessions",
        LockDirectory   => "../data/sessions"
    };
};
if ($@) {
 # since the first attempt failed, supply the
 # undefined value as the session ID argument
 # so that Session will generate a new session
 tie %session, 'Apache::Session::File', undef,
    {
        Directory       => "../data/sessions",
        LockDirectory   => "../data/sessions"
    }
}