[Koha] problem installing koha 2.3

I have problem installing koha2.3 here is the error that i face: read_config_file(/etc/koha.conf.tmp) returned undef at /usr/local/ koha/intranet/modules/C4/Context.pm line 195. Can't call method "config" on unblessed reference at /usr/local/koha/ intranet/modules/C4/Context.pm line 488. Problem updating database... Appreciate for your help thank you