Login issues

Hi There People,
Although I and my collegues are able to login successfully its been brought to my attention that none admin users are having issues registering or logging into their account.

Through a process of test I have found the following issues…

1. If you enter the wrong password when logging into the site, you are forwarded to a blank screen

2. If you try to request a new password, you are forwarded to a blank screen

3. When you sign in with the correct password, you are forwarded to a blank screen

4. After you successfully sign up as a new user, you are forwarded to a blank screen

Is there a setting that I have missed if not could you please provide guidance as to what could be causing this issue.

If you wish I can supply you with your own admin login details?

Thanks in advance for your time and assistance

You can access the website at http://www.yorkshire.net