It is impossible to avoid all kinds of bugs and problems in program development no matter what kind of language. ( Of course not include the program like “Hello World” ) Then we need to debug the program step by step. The debug environment is very important for the IDE and the Flex is no exception. Following tutorial teach you how to do the debugging in Flex Builder step by step. It’s very detail and with the screenshots. I think it may help you so much. If you have interesting please see the following article.