Hi rcb, it definitely sounds like a bug in screenshot captor -- give me a day or two and i will have a new build and try to fix the problem.
From what x16wda says, it's clear that it's not a general windows 8 problem, so it should be simple -- it sounds like it's something as simple as Screenshot Captor having an issue with a default printer or previous printer set..
One thing you might try if you feel like it, is to exit Screenshot Captor, then find and delete the screenshot captor settings file which will be under your documents folder, under DonationCoder\ScreenshotCaptor\ScreenshotCaptor.ini
And lastly, if you go to your windows control panel for Printers, can you check if you have your printer set as the Default printer?