[Koha] Error on web installer

Hello, I have installed Koha 3.4.6 on Ubuntu 10.04 using http://git.koha-community.org/gitweb/?p=koha.git;a=blob;f=INSTALL.ubuntu.luc... Now that the Koha is actually opening when I try to work my way through the webinstyaller I get the following message. Undefined subroutine &main::setlanguagecookie called at /usr/share/koha/intranet/cgi-bin/installer/install.pl line 25. Help?! Much thanks in advance

Leila