[otrs] Can't call method "png"

I'm upgrading from 1.2 to 1.3 but I got some problem with the new stats the system is new is Gentoo Apache 2 mod_perl mod_php fastcgi GD 2.16 GD::Graph 1.43 When I try to make a statistic in format graph (but also bargraph etc.) I get Can't call method "png" on an undefined value at /opt/otrs//Kernel/Modules/SystemStats.pm line 333.\n gentoo is compild with USE=png..... Ciao AleX