Hi.

I am struggling with the concrete 5 install. Every time the install fails with the following message displayed on screen:
{"error":{"message":"Call to a member function getPermissionKeyCategoryHandle() on null"},"errors":["Call to a member function getPermissionKeyCategoryHandle() on null"]}

Apache log shows:
[Mon Jun 08 14:09:37.041418 2015] [fcgid:warn] [pid 9662] mod_fcgid: stderr: PHP Fatal error: Call to a member function getPermissionKeyCategoryHandle() on null in /var/www/clients/client1/web7/web/concrete/src/Backup/ContentImporter.php on line 804, referer:http://concrete.local/index.php/install...

I have searched for the terms 'getPermissionKeyCategoryHandle' on this forum and general Google search, but no results.

I am using the latest version 5.7.4.2 on a Debian Linux (64 bit) under apache.

Can anyone advise how to fix this?

Thanks in advance.