I tried to load a new .world file today, but the following error messages always appeared:

Error [ModelDatabase.cc:228] No <database> tag in the model database database.config found here[http://gazebosim.org/models/]
Error [ModelDatabase.cc:287] Unable to download model manifests

After that, the GUI would still launch, but no model would appear unless I have them saved in the model folder on the local computer beforehand. It would display the message "Connecting to the model database" no matter how long I leave the GUI running. Another user seems to have the same problem (http://answers.gazebosim.org/question/6780/unable-to-find-models/). I also noticed that anything under the directory /wiki, /user_guide, and /models are completely down today. Can someone look into this?