As long as you use FitalyLetris...
it will not let you enter a typo. So when you complete the test it is correct. (I actually find that any typo slows me down enormously -- hear the bip? :-)
As far as Screen captures are concerned, you can use the one you want. Any gif/jpg capture will do. We just happen to recommend the excellent IA ScreenShot on the PPC because it is very good... and IA Style is a cosponsor of DP III, awarding 20 free registrations.