I have been running FB4 for quite some time by now with no real problems. I also have FB3 Pro installed.
I am moving all my projects to new box that runs Windows 2008 Server. I have installed FB3, and then FB4.
Now when I am opening properties of my project in FB4, under Flex Compiler I see red cross with "Flash Builder 4 only supports Flex SDK 3.0 or higher".
What exactly that means?
Needed to reconfigure SDKs.