Elxis 2008 and PowerBoard

[blue9600]

I have the next problem using PowerBoard, when i enter in it i get the following error:

PHP: Object of class pbSessionTable could not be converted to string
uri: index.php?option=com_powerboard&Itemid=111
path: /components/com_powerboard/powerboard.php
version: Elxis 2008.0 Stable rev1891 [ Olympus ] 10-February-2008 00:39 GMT+2
(4096): /home/giroestu/public_html/works/Chiari/components/com_powerboard/powerboard.php, line 120

and

PHP WARNING   
PHP: Cannot modify header information - headers already sent by (output started at /home/giroestu/public_html/works/Chiari/includes/Core/database.php:32)
uri: index.php?option=com_powerboard&Itemid=111
path: /components/com_powerboard/powerboard.php
version: Elxis 2008.0 Stable rev1891 [ Olympus ] 10-February-2008 00:39 GMT+2
WARNING(2): /home/giroestu/public_html/works/Chiari/components/com_powerboard/powerboard.php, line 147

any suggestions ?