Basic Settings Logs Me Out Of Admin Area

Hi, All functions on site seem to work ok, but when I try to access Basic Settings in the left menu It takes me to the Login Page.

All other admin settings can be accessed no problem.

Any advice appreciated, thanks.

On further examination I can access the Basic Settings using chrome (I was using opera before)

But there is no TimeZone dropdown in the settings as usual,

PLUS I am getting this error in the error_log file.

[02-Jan-2016 18:27:21 UTC] PHP Warning:  date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. in /home/user/public_html/domainname.com/inc/classes/BxDolProfileFields.php on line 1738

[02-Jan-2016 18:27:21 UTC] PHP Warning:  date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. in /home/user/public_html/domainname.com/inc/classes/BxDolProfileFields.php on line 1739

[02-Jan-2016 18:28:00 UTC] PHP Warning:  date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. in /home/user/public_html/domainname.com/inc/classes/BxDolTemplate.php on line 843

Any adivce, tips or suggestions apprecuiated thanks

I can now access the Basic Settings Using different browsers but the timezone drop down still doesnt show in Basic Settings like it does on my other sites.