Warning: Illegal string offset 'assign_for' || 'inherited_from'

Hi

I have recently set up a new installation in order to test whether this plugin will be suitable for a work project.

I have set up several users to be authors, restricted by page and all subpages.

I keep getting the following warning on each object role edit section:

Warning: Creating default object from empty value in C:\Users\anthonyw\Documents\Project Checkouts\wordpress-3.5-en_GB\wp-content\plugins\role-scoper\admin\item_roles_ui_rs.php on line 477

And I keep getting the following on the Page Roles page:

Warning: Illegal string offset ‘assign_for’ in C:\Users\anthonyw\Documents\Project Checkouts\wordpress-3.5-en_GB\wp-content\plugins\role-scoper\admin\admin-bulk_rs.php on line 981

Warning: Illegal string offset ‘inherited_from’ in C:\Users\anthonyw\Documents\Project Checkouts\wordpress-3.5-en_GB\wp-content\plugins\role-scoper\admin\admin-bulk_rs.php on line 982

Curiously, the last two errors only occur for one of my 4 defined users.

http://wordpress.org/extend/plugins/role-scoper/