Problems with PDF

[bludie]

Hello, I comes from Germany and my English is very bad...
I have a problem with the function PDF. If I want to create a document PDF on a page, the following mistakes appear:

PHP WARNING   
PHP: file_exists() [function.file-exists]: open_basedir restriction in effect. File(../../../images/logo.png) is not within the allowed path(s): (/var/www/html/web445:/tmp)
uri: index2.php?option=com_content&do_pdf=1&id=49
path:
version: Elxis 2008.0 Stable rev1891 [ Olympus ] 10-February-2008 00:39 GMT+2
WARNING(2): /var/www/html/web445/html/elx/includes/pdf.php, line 217
PHP WARNING   
PHP: Cannot modify header information - headers already sent by (output started at /var/www/html/web445/html/elx/includes/Core/database.php:32)
uri: index2.php?option=com_content&do_pdf=1&id=49
path:
version: Elxis 2008.0 Stable rev1891 [ Olympus ] 10-February-2008 00:39 GMT+2
WARNING(2): /var/www/html/web445/html/elx/includes/tcpdf/tcpdf.php, line 2479
PHP WARNING   
PHP: Cannot modify header information - headers already sent by (output started at /var/www/html/web445/html/elx/includes/Core/database.php:32)
uri: index2.php?option=com_content&do_pdf=1&id=49
path:
version: Elxis 2008.0 Stable rev1891 [ Olympus ] 10-February-2008 00:39 GMT+2
WARNING(2): /var/www/html/web445/html/elx/includes/tcpdf/tcpdf.php, line 2481
PHP WARNING   
PHP: Cannot modify header information - headers already sent by (output started at /var/www/html/web445/html/elx/includes/Core/database.php:32)
uri: index2.php?option=com_content&do_pdf=1&id=49
path:
version: Elxis 2008.0 Stable rev1891 [ Olympus ] 10-February-2008 00:39 GMT+2
WARNING(2): /var/www/html/web445/html/elx/includes/tcpdf/tcpdf.php, line 2482
FPDF error: Some data has already been output to browser, can't send PDF file

So, what can i do ?

Thanks