When you use httpService in Flex to read XML from a different domain (such as http://xml.weather.yahoo.com/forecastrss), you get a Security error accessing url error. But in the debug folder (bin-debug by default) it reads just fine. This is really annoying — I’m sure plenty of people have been tripped up by this security issue. Why does it only work in the debug folder? It turns out the bin-debug folder works only because [系统盘]:Documents and Settings[用户名]Application DataMacromediaFlash Player#SecurityFlashPlayerTrustflexbuilder.cfg sets it as trusted automatically. At actual runtime, it’s blocked by security. In other words, what we need to do is solve the security-block problem. So how do we fix it?