[otrs] Installation of otrs 2.2 on CentOS

I am trying to install otrs 2.2 on CentOS 4.4. After the installation by the command yum install otrs-2.2.2-01.i386.rpm the apache fail to start. The error message appairs : Starting httpd: (13)Permission denied: httpd: could not open error log file /var/log/httpd/error_log. Unable to open logs The rights on the file are corrects. Is any other configurtion on apache server to do? -- Agim Cami