Problem with paypal IPN not updating pledges on website

Hi

I have installed the fund-raising plugin and have set the ipn to http://sidgardendesign.co.uk/wordpress/wp-admin/admin-ajax.php?action=wdf-ipn-return-paypal as it shows in a lot of the support requests I have searched.

The IPN history shows two transactions as being retried. So no pledges are being updated on the website.

They show an Http response code of 404 and a notification url of http://sidgardendesign.co.uk/wordpress/wdf-payment-return/paypal/

Any ideas why this might be happening?

regards

Ian Stratton