The first thing you should do to find the cause is to examine the file /var/log/pandora/pandora_server.error and according to the following possible error messages, there are the following solutions:
Starting Pandora FMS Server. Error logging activated. DBD::mysql::st execute failed: Table 'pandora.tagent_module_inventory' doesn't exist at /usr/local/share/perl/5.10.0/PandoraFMS/DB.pm line 199.
In this case it’s because in previous installations you left Pandora Server Enterprise installation files behind.
Specifically, it should be the file /usr/local/share/perl/5.10.0/PandoraFMS/Enterprise.pm. If you delete it, the Pandora Server won’t go down on startup.