Date_default_timezone_set(): Timezone ID '/' is invalid

Please try the following from linux shell:

fwconsole mysql
select * from sysadmin_options where sysadmin_options.key like 'tz%';

You should see two entries:

+--------------+---------+
| key          | value   |
+--------------+---------+
| tz_continent | America |
| tz_region    | Chicago |
+--------------+---------+

If either of these are wrong, do the following from within MySQL:

update sysadmin_options set value='America' where sysadmin_options.key='tz_continent';

This will change the continent to ‘America’. To change the region:

update sysadmin_options set value='Chicago' where sysadmin_options.key='tz_region';

That will give you CST. See if that gets you into the GUI again, and then adjust the settings from sysadmin as needed. Type exit to leave MySQL.