I copied the folders and files you sent me into Configuration folder.
There was no change unfortunately. Still "Add to cart button" is not active.
And I found that there are other functions that don't work;
-View cart button
-Clear cart button
-Continue shopping button
-Update cart button
-Updatable text field
-Updatebale check box
Insert checkout button
And these are active and DO work;
-Payment Gateway credentials
So then I deleted .dat file --> no change.
Then I uninstalled eCart6 from Extension Manager, rename the Configuration folder, copied eCart file you sent me into a new Configuration folder.
Still no change, but this time eCart is not recognized in Extension Manager, thus no eCart menus on the menu bar in DW. I can see the eCart functions in Server behavior panel though.
What else can I try?
Thank you for your help.