When loading large DNGs with Camera RAW 4.4 (for example, DNG dimensions are 9984x6656) CS3 says "cannot open the image because this is not a right kind of a document". EXACTLY THE SAME file is loaded without a problem using Camera RAW 3.7 and 4.0 (did not test other versions). Have you specially prevented loading of large files? Wouldn't it be better to provide this as an option? It's a real disappointment - new version of plugin CANNOT do the thing that older versions CAN. (Simply using older version is not an option, as I need to load RAWs from new cameras, like Canon 450D).
Dear Adobe, please correct this problem :)
It might be wise to give some insight like how the DNG was created, by what version of what software, if ACR is hosted in Photoshop or Bridge... What platform you are using, how much RAM, memory allocation, etc.