My installation of Flash Builder Beta 2 does not appear to have the "File > Import Flex Project (FXP)" menu item needed to import an FXG file/project, described here.
I have examined Flash Builder's "Customize Perspective..." options, and none of the options available appear to have the potential to add this missing menu item.
I am running Flash Builder Beta 2 (build 253292) on Eclipse 3.4.2 (build M20090211-1700) on Max OS X (version 10.5.8).
Strange. I had a similar problem with the non-appearance of the debug icon (now resolved). Improper installation sequence, perhaps? If so, then presumably other people would be encountering these problems too, yet I can find no other postings of similar problems from others.