Hi Phil, I had these problems with these two programs and was told that it could be that the files produced by the 1600 are huge and may be too big for Sharpcap and Registax to cope with. I then tried Firecapture and Autostakkert and found that the problem didn't occur. It may have been something completely different but maybe give it a go, nothing to loose really.
Just as an aside, I've been using Startools for some time with a Canon 40D with some success, but trying to process a 192,000Kb autosaved file from the 1600 makes Startools give up the ghost half way through. It could be coincidental but I reckon that file size is about as innocent as the man on the grassy knoll.
Pip