I never knew that DPP allowed you manage, copy, and paste files. Isn't this what that "Image Browser" software supposed to do for you?
I've used successive versions of DPP for almost ten years, and that has always worked for me. 4.5.10 has a problem with drag and drop, but cut and paste have always worked properly.
I've always assumed that Image Browser was merely a successor to Zoombrowser, i.e. a dumbed-down editor for P&S users who don't want to bother learning a serious editor.