@MiDo
Could be a multitude of problems. For starters, when you move over, did you check to make sure your conf_global.php reflected your new database details, and the path is correct?
Since you are unable to login to ACP, download the attached file and upload it to your web root. Then access it via yoursite.com/ips4.php - check to make sure there are no errors (in red). This will also check your folder and file permissions to see if the necessary files are writable.
ips4.php