[Typo3-shop] tt_prducts error message in Typo3.7

[Volker Graubaum]

Hi Frank,

I think it`s a PHP/Windows thing. You have to be sure that functions and 
options are only one time in the class.

Under linux the zk_products shop runs very well with 3.7 
(www.qualitaetsstruempfe.de), but I got an analog error with a double
written function under windows.

Greetings Volker