In the file simpleshare.module there is an error in the use of the t() function in line 105 that produces a recoverable error after creating an unpublished node.

Currently:

drupal_set_message(t('Sorry, you cannot share unpublished content. Mark it as published and try sharing again.', 'warning'));

It should be:

drupal_set_message(t('Sorry, you cannot share unpublished content. Mark it as published and try sharing again.'), 'warning');