problem capturing VDO from FS

hi, I'd like to capture VDO from FS using a TV-out VDO card (GF2 MX400) connected to a Panasonic VCR recorder via AV cable. (and turned on clone mornitor function) But the problem is I can't record anything, when I play it back it's just all silent black video. I also did the samething as an experiment with my VDO capture card (connecting the AV cable from the TVout VGA card to the AVin of the capture card) and the picture shows OK so that means that there is nothing wrong with the VDO out feature. But I cannot use the computer to record FS VDO while playing FS cause that wil hog too much CPU power and mak the game unplayable. Wondering why I can't record anything using the VCR...