Moving WordPress to new server, domain & databse HELP!

Hi,

Right, need some help from someone clever out there.

We have a CMS which we have the main webisite in, and have installed WordPress into a sub directory of the website (i.e http://www.website.com/blog). That works fine.

We have been instructed by our client to move the whole website including the blog to a new host, new domain name and new database.

The main website works fine, the website/blog (frontend) works fine, but the backend shows this:

Warning: require(./wp-blog-header.php) [function.require]: failed to open stream: No such file or directory in /home/fhlinux221/t/test.cobbpr.com/user/htdocs/blog/index.php on line 17

Warning: require(./wp-blog-header.php) [function.require]: failed to open stream: No such file or directory in /home/fhlinux221/t/test.cobbpr.com/user/htdocs/blog/index.php on line 17

Fatal error: require() [function.require]: Failed opening required ‘./wp-blog-header.php’ (include_path=’.:/usr/share/pear-php5′) in /home/fhlinux221/t/test.cobbpr.com/user/htdocs/blog/index.php on line 17

We have been going out of our minds trying to find the solution. The wp-config.php file has been updated to have the new database details.

What are we doing wrong?