Hey Mark,
Thanks for sharing the error log entries, it helped me to track down the issue quickly.
I found the source of the issue, arrays that use curly braces are deprecated in version 7.4 of PHP, and there is a line of code in the function _showCheckbox that uses them.
I've added a fix to the codebase of CMS Builder so that the issue will be resolved in the next release.
You can manually patch the issue in your version CMS Builder by editing [CMSB Directory]/lib/menus/default/edit_functions.php line 794 and change it from this:
else if ($record && @$record{$fieldSchema['name']}) { $checkedAttr = 'checked="checked"'; }
to this:
else if ($record && !empty($record[$fieldSchema['name']])) { $checkedAttr = 'checked="checked"'; }
Cheers,
Greg
Greg Thomas
PHP Programmer - interactivetools.com