Undefined property: stdClass::$field_...

I use the following combination of view modules:

Views Accordion (display: eva - Entity View Attachment) with arguments
-> Views Field View
---> Views Summarize (display: eva - Entity View Attachment) with arguments

I have correct results but it brings me some errors

Notice: Undefined property: stdClass::$field_inv_date in eval() (line 2 of drupal-7.19/modules/php/php.module(80) : eval()'d code).
Notice: Undefined property: stdClass::$field_wh_action in eval() (line 7 of drupal-7.19/modules/php/php.module(80) : eval()'d code).
Notice: Undefined property: stdClass::$field_wh_cont in eval() (line 8 of drupal-7.19/modules/php/php.module(80) : eval()'d code).
Notice: Undefined property: stdClass::$field_inv_date in eval() (line 2 of drupal-7.19/modules/php/php.module(80) : eval()'d code).
Notice: Undefined property: stdClass::$field_wh_action in eval() (line 7 of drupal-7.19/modules/php/php.module(80) : eval()'d code).
Notice: Undefined property: stdClass::$field_wh_cont in eval() (line 8 of drupal-7.19/modules/php/php.module(80) : eval()'d code).

Do I have to do something?