Can be a pain. (Welcome to windows.) Three simple rules. Do not run the installer from the desktop, it won’t install properly (apparently a known windows issue). Secondly if you’ve installed it and you’ve got problems, try running:

http://korsakow.net/tools/qtjavahelp.jar

Thirdly, when you install QuickTime on Windows the default is to not install QuickTime for Java, so when you install it tick the install Java option (or go back and reinstall and tick this option). This solves the generic “Korsakow won’t run on windows” problems. Often helps. After that, we need to get into specifics, these are two known generic issues.