You can start the server using the tigase file found in the scripts sub-directory of Tigase server base directory. There, select the type of linux you have, debian, gentoo, mendriva or redhat. In the root server directory type the following command:
./scripts/{OS}/init.d/tigase start etc/tigase.conf
Where {OS} is your *nix operating system.
and you should get the output like this:
Starting Tigase: nohup: redirecting stderr to stdout Tigase running pid=18103