Registration On/Off – Network Settings?

Hi

I’m struggling with various issues since changing to the responsive theme 🙁

– this one is about registration.

I want new registrations to be able to create their own passwords, so have selected

General Settiings > Registration > Allow Visitors to Create Passwords > On

– but there is a message displayed above saying ‘ Registration on/off options are part of WordPress Network Settings (link) – if I click on the link I get ‘ You do not have sufficient permissions to access this page’ – I only have one admin account and this is not a WP multisite install so I can not seem to turn registration on,

As things stand anyone can create a listing without creating a username/password.

Am I missing something here ?

Thanks
Alan