Login Error appeared after uploading basic php file

On the live server we have got an issue logging in. I updated to 4.1.2 early this morning. I made a change to a simple php page this morning and now no-one can log in. We get the following error for Login.php which seems to point to the login sequence, but I have changed nothing in this area for a long time.

Can anyone give me some pointers as to what to look at?

1. code: 0
2. file: "/var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/modules/dbconnector.php"
3. line: 70
4. message: "Too few arguments to function modules\\dbconnector::single(), 2 passed in /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/lib/App.php on line 195 and exactly 3 expected"
5. trace: "#0 /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/lib/App.php(195): modules\\dbconnector->single(Object(stdClass), 'q_current_user')\n#1 /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/lib/App.php(159): lib\\App->execSteps(Object(stdClass))\n#2 /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/lib/App.php(127): lib\\App->execSteps(Array)\n#3 /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/lib/App.php(116): lib\\App->exec(Object(stdClass), false)\n#4 /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnectLib/lib/App.php(94): lib\\App->exec(Object(stdClass))\n#5 /var/www/vhosts/daviesandgray.co.uk/httpdocs/dmxConnect/api/DG_Admin/Login/Login.php(8): lib\\App->define(Object(stdClass))\n#6 {main}"