I have an issue which I don't think is specifically a Screenshot Captor issue (as I get the same problem using the generic XP print-screen functionality), but I thought I'd ask here and see if anyone had any idea what's going on.
Running xp/sp3 with 4gb memory and a dual monitor setup (1920x1200 each) on a Radeon 3850 (512MB), when I take a screen shot, it doesn't always capture to the clipboard. When I use XP's native prtscrn and try to paste it into various programs (paint, paint.NET, GIMP), I get various error msgs ("Error getting clipboard data", or "There is no image data in the clipboard to paste").
Interestingly, when I use Screenshot Captor, it successfully shows the thumbnail version, and can save the image to file, but copying the image to the clipboard and trying to paste results in the same error msgs. Sometimes I get an extremely grainy black-and-white version of the screen shot.
I have a vague sense this might be a memory issue, because despite having the maximum memory possible installed (on a 32-bit XP install), I do always have a lot of programs running, and (1920x1200x32bits) x dual monitors = lots.