I've implemented OpenWorld 2.2 (HP-UX), 2.1/2.4 (AIX) and 2.5 (Win2k + HPUX) on Baan IVc4. All were fairly straight forward. There are some min. requirements like porting set, JDK version, and tools patches.
What do you plan to do? Do you plan to use the Domain packs and integrate to standard Baan using the standard BOI's? Have you customized Baan, and want to develop your own BOI's?
Which components of OW are you planning on using?