Delicious is currently undergoing a data center move, but there are outstanding issues which is affecting Delicious Post. (Delicious is owned by Science LLC, and AE Creations is not affiliated with it, nor has any involvement in the Delicious website.)
These issues may cause problems when posting links to your Delicious page. You may receive error messages such as "error posting link" or "504 GATEWAY_TIMEOUT".
All I can say is to try posting again later. There isn't much else I can suggest, as these errors are being relayed back from the Delicious service.