Blank screen when accessing blocks page

Using Drupal 6.4 with modified a3_atlantis theme. Only minor modifications in theme's css file and modification to images. Have several custom modules installed but I was testing the site on a local machine and I could access the blocks admin page with this theme, but as soon as my site went live on the net I get a blank white screen when I try to access the same admin page. If I select another theme first (a default like garland) then there is no problem accessing the blocks.

The error i get when a return to another admin page is:

* warning: main() [function.main]: open_basedir restriction in effect. File(/page.tpl.php) is not within the allowed path(s): (/home/httpd/vhosts/linxs.com.au/httpdocs:/tmp) in /home/httpd/vhosts/linxs.com.au/httpdocs/testsite/themes/a3_atlantis/page-admin-build-block.tpl.php on line 1.

* warning: main(page.tpl.php) [function.main]: failed to open stream: Operation not permitted in /home/httpd/vhosts/linxs.com.au/httpdocs/testsite/themes/a3_atlantis/page-admin-build-block.tpl.php on line 1.

* warning: main() [function.main]: open_basedir restriction in effect. File(/page.tpl.php) is not within the allowed path(s): (/home/httpd/vhosts/linxs.com.au/httpdocs:/tmp) in /home/httpd/vhosts/linxs.com.au/httpdocs/testsite/themes/a3_atlantis/page-admin-build-block.tpl.php on line 1.

* warning: main(page.tpl.php) [function.main]: failed to open stream: Operation not permitted in /home/httpd/vhosts/linxs.com.au/httpdocs/testsite/themes/a3_atlantis/page-admin-build-block.tpl.php on line 1.

The mentioned php files have been given write, read and execute access (except public users doesn't have write access) and I have not modified the php except to add a credit to the footer of the template.

I need some help, as it makes it near impossible to add/modify blocks.

Thanks in advance.