get the following errors when using sigma one as administrator theme

Warning: Invalid argument for foreach() in element_children() (regel 6465 van /srv/www/web/includes/common.inc).
Warning: '#children' in drupal_render() (regel 5930 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5940 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5978 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#printed' in drupal_render() (regel 5985 van /srv/www/web/includes/common.inc).
Warning: Invalid argument supplied for foreach() in element_children() (regel 6465 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5930 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5940 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5978 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#printed' in drupal_render() (regel 5985 van /srv/www/web/includes/common.inc).
Warning: Invalid argument supplied for foreach() in element_children() (regel 6465 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5930 van /srv/www//web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5940 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#children' in drupal_render() (regel 5978 van /srv/www/web/includes/common.inc).
Warning: Illegal string offset '#printed' in drupal_render() (regel 5985 van /srv/www/web/includes/common.inc).

and also Notice: Undefined index: overlay in tabs_block_renderable_array() (regel 70 van /srv/www/web/sites/all/themes/sigmaone/sigmaone/vtcore/plugins/layout/blocks/tabs/tabs.block