vicky,
I am unfamiliar with the lv_vfw.llb, and have not used it before. However, I noticed that you stated that you are able to grab in color, just not snap in color. If this is the case, why not just perform a grab and then extract a single buffer from this grabbed data, which would likely be in color? This seems like a possible solution to the issue that you are seeing.
Other than that, I really don't know enough about the lv_vfw.llb to be of much help on this issue. Hopefully another member of this forum will be able to assist you with this software.
Regards,
Jed R.
Applications Engineer
National Instruments