40D RAW capture problems

[Redback51]

Good evening all...I write this because I am all of a sudden having problems capturing raw images when using exposure bracketing. My camera's set for medium jpg and large RAW images.

For a number of years I've been using a 4GB SanDisk CF card and recently upgraded to a 16GB card (simply because I was going bush for a few weeks and needed the extra storage). I never had a problem using AEB with the 4gig and, initially, none with the 16gig. But then I noticed that only the occasional RAW image from a bracketed exposure would download and then finally, none at all. The RAW files appear to have been replaced with a file with a .JPG extension (as distinct from .jpg). So, what I generally get now with a bracketed exposure is three .JPG files instead of RAW files, and three .jpg files.

One other thing that's also been happening in association with the lack of RAW images is that, at times, the 3-burst capture takes an inordinate amount of time to download to the card.

The battery is new, being bought at the same time as the 16GB card.

Everything else is per how I've been using the camera since I bought it new.

Any clues what's happening? Any advice on how to fix would be gratefully appreciated.

Cheers