the error is gone. It came up when I tried to deinstall eCart 4.5.0
Right now I deleted the Configuration folder in DW9. So i needed to install all extension again. Now the error is gone.
The problem I got with eCart is, that I dont know, how many pages I need and where to put which serverbehavior.
I get to the point, where the user has to click the checkout button. Till there all is easy.
Then I want to setup, a paypal paymet like you got on your site. The customer data comes sout of the database, cause the user is logged.
I use the checkout wizard, but there I cant choose Express Checkout.
So I went to the German PayPal site and got my own API for that express checkout.
and, now, I dont know where to start.
I want, if the payment was successful, update the user database table, and set a flag that its payed.
this, is what I need, but dont understand to start.