A possible explanation is that more "recent" versions of CGI::Session use the "recently" added refaddr method of Scalar::Util. The latter is not pure Perl so cannot just be copied to your web hoster.

If your hoster doesn't have the required version of S::U you'll be out of luck.

Either ask your hoster to install the latest version of C::S or failing that copy a version that doesn't use S::U.

See also: Re: CGI::App::Session param not getting saved