Errors making changes to the sample db

[Chewie9999]

I have copied your ipam.db.sample to ipam.db, and changed the permissions so that both owner (root) and the webserver group have RW access, but when I try and add a new network, or delete one of the sample networks, nothing happens.
There's no error in the web page, but I get the following in my apache logs:

[Sun Mar 03 16:02:18.680789 2019] [:error] [pid 13554] [client x.x.x.x:45654] PHP Fatal error: Call to a member function lastErrorCode() on boolean in /var/www/redmine/public/SimpleIPAM/system/database/drivers/sqlite3/sqlite3_driver.php on line 300, referer: http://x.x.x.x/SimpleIPAM/index.php

This could have been due to RW permissions problems, but I still can't make changes, even though I have restarted the web server.
My server is Apache/2.4.10.
PHP reports the following:

PHP 5.6.40-0+deb8u1 (cli) (built: Feb 17 2019 01:19:33)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies

# php -m | grep sql
pdo_sqlite
sqlite3

I have just installed sqlite3 itself:

# sqlite3 --version
3.8.7.1 2014-10-29 13:59:56 3b7b72c4685aa5cf5e675c2c47ebec10d9704221

But that's made no difference.

Unfortunately PHP isn't my strong point.
Please let me know what I can do to help troubleshoot this problem.
Thanks!

[Chewie9999]

It turned out it was a permissions problem on the web server directory. It would be good if an error message could be displayed if the permissions are not set correctly!