log in via FTP to your server: ow_plugins/oaseo/controllers/admin.php file.
Try commenting out or deleting following lines:
$canonicRedirect = new CheckboxField('canonic_redirect');
$canonicRedirect->setLabel($this->service->text('canonic_redirect_label'));
$canonicRedirect->setDescription($this->service->text('canonic_redirect_desc'));
$canonicRedirect->setValue((bool) $this->service->getConfig(OASEO_BOL_CanonicService::CNF_REDIRECT));
$form->addElement($canonicRedirect);
Save your changes and try checking admin panel interface again.