These instructions apply only to the Flex 2.0.1 plug-in for Eclipse. If you have an older version of the Flex 2 plug-in, upgrade to the 2.0.1 version.
Note: Ensure that you install the Flex 2.0.1 plug-in before following these steps.
There is a conflict between the version of Xerces used by RAD 7 and the version required by Flex Builder 2. Edit the eclipse.ini file so that the xercesImpl.jar file in the Flex 2 SDK is used instead of the default version. Set the following:
-Xbootclasspath/a:[install-path]\Flex SDK 2\lib\xercesImpl.jar
Change [install-path] to the location of the Flex Builder 2 plug-in on your system.