PHP error when trying to access styles panel

Hi there I was referred to here from
http://www.phpbb.com/community/viewtopic.php?f=69&t=1214645&start=930

I have not changed or edited anything on my server before this started and recently I have been getting the following errors when I try to access my Styles in ACP

The error is as follows

[phpBB Debug] PHP Notice: in file /includes/acp/acp_styles.php on line 647: file_exists() [function.file-exists]: open_basedir restriction in effect. File(./../styles/rss_template.xml/style.cfg) is not within the allowed path(s): (/customers/mydomain.com/mydomain.com:/tmp:/var/www/diagnostics:/usr/share/php)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 150: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3528)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 152: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3528)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 153: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3528)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 154: Cannot modify header information - headers already sent by (output started at /includes/functions.php:3528)

I have tried a search on here and in the phpbb3 forums to no avail and I was wondering if any kind person could point me in the correct direction?

Regards
Steve