In the template.php file it says in line 125 (if I haven't messed above):

$required = $required ? 'class="form-required" title="'This field is required."' : '';

and should say:

$required = $required ? 'class="form-required" title="'.t('This field is required').'."' : '';

for 'Locale' sake.

(I'm not sure but I think the status is ok as 'code needs review'. If you find I'm doing anything wrong, please let me know)

Have a good day,
hip