[otrs-de] otrs server error 500

Hello all, I use kubuntu daper and I just install otrs 2.04 on apache2. But I get an internal server error 500 when I go to ../otrs/installer.pl I tried the setpermission script with: 'SetPermissions.sh /usr/share/otrs otrs:www-data' but this gives some courious permissions with otrs:nogroup on the files. I think this is not correct. Is the script not working? Can I do something to set permission correct? Or is something else wrong? Can someone help? tia stefan