For me, since BST updated the code and converting the YUV colorspace, the grabing works perfectly for me. Using Mode1, true, and only.
Make sure you using the latest version AND that you have checked the "Convert caputered images in software" for both YUV modes. (the Mode1 is there presented as YV12 and Mode2 as YUV2)
...and don't forget the directory! :P