I checked everything again but still not working.
In the documentation under "legacy changes":
1. Administration Tool App Setup
I did this but still not working.
The text "MODULES_ADMIN_MENU_PAYPAL_HEADING" appears when i add "include(DIR_WS_BOXES . 'paypal.php');" to myadmin/includes/column_left.php.
How can i install the app?
If I click under modules -> PayPal Payments Standard on "install" or Manage App i always get to the same page (picture above) and nothing happens.
Only the get parameter change in the URL
Under "Minimum Requirements" it says
"PayPal App - The PayPal App can be used from osCommerce Online Merchant v2.2RC2a (2008) onwards, and is optimized for and bundled with v2.3.5."
I see the following modules:
PayPal Express Checkout
PayPal, Lastschrift, Kreditkarte oder Rechnung
PayPal Payments Pro (Direct Payment)
PayPal Payments Pro (Hosted Solution)
PayPal Payments Standard