1.Flex Builder是需要输入序列号注册的（至于怎么找序列号，网上有很多）

help->manage flex licenses

如果输入序列号仍然有水印，那么参考这里的文章 http://flexman.info/2008/11/13/entering-serial-number-of-adobe-flex-builder-watermarks-still-on-charts/

1. On the Project menu, choose Build Automatically to turn off this option. If the option is already turned off (deselected), do not complete this step.

2. Choose Project > Clean. 3. Choose Project > Build. 4. (Optional) Choose Project > Build Automatically to turn on this option again, if desired.

如果还没有解决 参考这里 http://www.riachina.com/showtopic-9363.aspx