I have a BOLD 184.108.40.206 and it works for me.
Basically all screenshot tools for the BB do exactly the same, they use javaloader to get a screenshot. My ScreenShooter only wraps a GUI around the command line tool. So I can't understand why that happens.
The "white screen" is normal under certain circumstances and should appear even when you use the command line tool itself when:
-you have encryption enabled
-your BB is locked
-when the screen is dark or the BB is holstered
That phenomenon exists since Blackberry introduced transparency and shades in their themes.