FB 4 is not part of the LiveCycle installer. If you would like to customize the workspace or write Flex appications in LiveCycle you would need the Flash Builder to be installed. If you evaluate the software you can download a trial from the adobe.com homepage under software download for free.
If you purchase a licensed component from LiveCycle you will be entitiled to install up to 5 workstations with the FB 4 software
hope this helps
rgs
dieter