"PHP Fatal error: Uncaught Error: Call to a member function" during install

Ubuntu Linux 16.04.2
10.0.31-MariaDB-0ubuntu0.16.04.2

MySQL root password definitely correct as I'm using Webmin and can copy it from there & paste it into the shell window. I have also tried typing it in, just in case. All else is default. I have created a test DB in Webmin & that's fine.
Running the ISPConfig installer results in:

Code:

PHP Fatal error:  Uncaught Error: Call to a member function queryAllRecords() on null in /root/install/ispconfig3-stable-3.1-b1337668df50d3672b348708a4a3949b2fca1f60/install/lib/installer_base.lib.php:238
Stack trace:
#0 /root/install/ispconfig3-stable-3.1-b1337668df50d3672b348708a4a3949b2fca1f60/install/install.php(294): installer_base->configure_database()
#1 {main}
  thrown in /root/install/ispconfig3-stable-3.1-b1337668df50d3672b348708a4a3949b2fca1f60/install/lib/installer_base.lib.php on line 238

Any ideas?

 

Was searching for a solution too after having the same problem just minutes ago ;-)
(except I am on 16.04.3)

 

Possibly relevant extra information:

I was repeating a successful installation i had done just a few days ago after a new disk was installed... but this time it was on Ubuntu 16.04 and PHP 7. The previous install was under Ubuntu 14.04 and PHP 5.6.

 

https://www.howtoforge.com/community/threads/php-isp-installation-problem.77258/

 

Thanks - fixed! ISPConfig now installed & working

I did do a search but obviously not with the right search terms to find that thread <sigh>

 

Worked, Thanks Florian030!
@ITFixt: no sweat, that thread was not there yet when you posted ;-)