After upgrade to drupal 7: Notice: Undefined index: format in popup_block_form_alter()

Hi,

after upgrading to Drupal 7 I get the following error message when editing some blocks:

Notice: Undefined index: format in popup_block_form_alter() (Line 58 von C:\wamp\www\project\sites\all\modules\popup\modules\popup_block\popup_block.module).

Best,
Tobias