[dev] Example don`t work

Hello, I try use example from Developer Manual "HelloWorld". When I try click link "HelloWorld" in NavBar I see strange error. Message in OTRS log "[Fri Apr 4 15:06:35 2008][Error][Kernel::System::Web::InterfaceAgent::Run][185] ???" Message in Apache log "ERROR: OTRS-CGI-10 Perl: 5.8.8 OS: linux Time: Fri Apr 4 15:06:35 2008 Message: ??? Traceback (1806): Module: Kernel::System::Web::InterfaceAgent::Run (v1.23) Line: 185 Module: /usr/share/otrs/bin/cgi-bin/index.pl (v1.81) Line: 47 " What I do incorrect. Please help me. P.S.: