Error after install and make settings-localisation

I installed 3.1 b6, went to settings, set localisations, saved and got the following error:

warning: Parameter 1 to CRM_Admin_Form_Setting_Localization::formRule() expected to be a reference, value given in C:\Dokumente und Einstellungen\BUM\Eigene Dateien\Tikixampp\xampp\htdocs\drupal\sites\all\modules\civicrm\packages\HTML\QuickForm.php on line 1596.

unrecoverable error
Sorry. A non-recoverable error has occurred.

QuickForm Error: unknown error

Return to home page.

Error Details:

Array
(
[callback] => Array
(
[0] => CRM_Core_Error
[1] => handle
)

[code] => -1
[message] => QuickForm Error: unknown error
[mode] => 16
[debug_info] => Form rule callback returned invalid value in HTML_QuickForm::validate()
[type] => HTML_QuickForm_Error
[user_info] => Form rule callback returned invalid value in HTML_QuickForm::validate()
[to_string] => [html_quickform_error: message="unknown error" code=-1 mode=callback callback=CRM_Core_Error::handle prefix="QuickForm Error: " info="Form rule callback returned invalid value in HTML_QuickForm::validate()"]
)