Debugging is not supported under current trust level settings.

Situation: Your dearest portal refuses to load default.aspx and you wonder what tantrum she is throwing. You thought it's the settings in Tools -> Internet Options -> Security, but no matter what you change, it still doesn't work.

Cause: You have added in a new application (e.g. an ASP.NET object going with the .dll tag) to a subsite. This is so subtle that you didn't think that it will be going to affect your other buddies.

Solution: Go to the web.config file in the root directory and change the cranky woman's trust level: [trust level="Full" originurl=""] under the [system.web] tag. The default should be "WSS_Minimal" which basically means she doesn't trust you enough to bring your friends home.