404. That’s an error.
The requested URL /add?source=atgs&feedurl=http%3A//zaikou.txt-nifty.com/whats_new/index.rdf was not found on this server. That’s all we know.
/add?source=atgs&feedurl=http%3A//zaikou.txt-nifty.com/whats_new/index.rdf