I hard coded the url as well, but now got this error:
Request failed for https://www.rt103.nl/wp-content/plugins/contact-form-7-to-database-extension/export.php?form=wijn2013 returned code 500. Truncated server response: <!DOCTYPE html> <!– Ticket #11289, IE bug fix: always pad the error page with enough characters such that it is greater than 512 bytes, even after… (use muteHttpExceptions option to examine full response). (line 66, file “Code”)