Did you try this recently? It seems to me that YAAC is expecting a file called messages-1.html located on the webserver of the DC but I'm not able to locate this file via http. I know you can read the messages-[date/time].txt files via ftp but I guess we need to talk to the author of YAAC to solve this.
Maybe @Seasalt have found a solution?
BTW: Thanks for the warning about the APRS-IS loop!