The software to use to capture frames from DivX files is called virtualdub. It works like a dream, you just move the scrollbar to whichever frame you want and capture it to your clipboard.
Here's the link to their website:
"Virtualdub.org"
That only took me about a month to find! ;)
Thanks for the link! I have been looking for something like this. I have software that supposedly can do captures, but it keeps crashing. I'll give this a try.