The solution is pretty simple. You are facing a path issue with my php.ini:
Replace
open_basedir=/home/OLDdhostingusername/public_html:/tmp::/home/OLDhostingusername/temp_joomla:/home/OLDhostingusername/public_html/logs
With
open_basedir=/home/NEWhostingusername/public_html:/tmp::/home/NEWhostingusername/temp_joomla:/home/NEWhostingusername/public_html/logs
This will clear your issue.