Unfortunately due to the internal reorganisation of RISC OS 6, ViewFinder is no longer supported, and wont be unless John Kortink comes out of retirement and re-writes his code, or ROL write a driver for ATi cards from scratch, neither of which I would hold my breath for. This means its not even worth trying for me, as going back to small flickery VIDC modes from 2048x1536x32bpp that both my machines run at, is unconscionable.
Another unfortunate feature is continuing nonsense over the Shared C Library. The version ROL supply in ROM is not fully compatible with applications that are built with up to date versions of the C/C++ development environment, and attempts to load the required Castle SCL result in a warning dialog of instability (although apparently does then load). I don't care who's fault this it is that a proper SCL is not provided, either ROL or Castle, but it needs sorting out as it is intolerable it does not work correctly with the official platform development suite. Until this is sorted out, I'm afraid an incompatibility issues regarding software I've written, ported or maintain will have to be addressed by ROL.