The labels 'Horizontal tabs group' and 'Multipage group' can't be translate.

I don't know how to create a patch, but there is only 3 letters 't' to add in file field_group.module, in the lines 266, 278, and 330.
(line numbers correspond to the 7.x-1.1 version, but the problem is still here in the 1.x-dev)

'label' => t('Horizontal tabs group'),
'label' => t('Multipage group'),
'label' => t('Horizontal tabs group'),