There have been a lot of changes to OpenCL in this Lion release. One of them prevents the app from starting after installing the Lion 10.7.5 update.
You will need to use the Mac Finder to do this:
- Open the Finder.
- Using the Finder menu, click on this menu item: Go > Go to Folder …
- Enter: ~/Library/Containers
- Move the folder com.centcom.FractalArchitect2 to the Trash.
- Restart the application.