Problemas instalando CometChat

Hola estoy usando “CometChat” en mi red social Jomsocial, pero me aparece este error al instalar..

[color=#ff0000]
Warning: include_once(/home/xxxxxx/public_html/relacionesocacionales.com//application/libraries/OFC/JSON.php) [function.include-once]: failed to open stream: No such file or directory in /home/xxxxxx/public_html/relacionesocacionales.com/cometchat/integration.php on line 19

Warning: include_once() [function.include]: Failed opening ‘/home/xxxxxx/public_html/relacionesocacionales.com//application/libraries/OFC/JSON.php’ for inclusion (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/xxxxxx/public_html/relacionesocacionales.com/cometchat/integration.php on line 19

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at /home/xxxxxx/public_html/relacionesocacionales.com/cometchat/integration.php:19) in /home/xxxxxx/public_html/relacionesocacionales.com/libraries/joomla/session/session.php on line 423

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /home/xxxxxx/public_html/relacionesocacionales.com/cometchat/integration.php:19) in /home/xxxxxx/public_html/relacionesocacionales.com/libraries/joomla/session/session.php on line 423

Warning: Cannot modify header information – headers already sent by (output started at /home/xxxxxx/public_html/relacionesocacionales.com/cometchat/integration.php:19) in /home/xxxxxx/public_html/relacionesocacionales.com/libraries/joomla/session/session.php on line 426
404 – Componente no encontrado[/color]

La version que he intentado instalar es la 3.0.1 , la 2.0.4 y la 4 y todas me dan error al entrar a install.php

Alguna solucion?
Cual es la version mas estable para JomSocial 2.2.1 ?

Actualmente uso joomla 1.5.24

Gracias por sus comentarios