I found the corrupted files and recreated them so I can now connect to the DB using Dreamweaver.
With the risk of being a pain for you but I have one more problem: Since quite some time I have not been able to see the Universal e-mail in the server behavior. Now Dreamweaver only displays the Dynamic list and text fields in the server behavior window.
I for example are not able to see the eCart Store Cart Details in DB nor do I see the Universal Email in the server behavior window of the confirm.php page for example and therefore are also not able to access those in the server. That is true for all pages so even AuthorizeNet or PayPal server behaviors are not displayed in Dreamweavers Server Behavior window.