Sorry I don't have an answer but I do have the same problem with the installation on one of my PCs. On other PCs it works fine. None of the tools work because if I click on say 'merge PDF' the window to add files isn't active. It's just greyed out. Nothing happens at all if I click on eg 'open PDF reader' or 'import from scanner or camera'.
Uninstalling and reinstalling doesn't help. I have the latest version. This doesn't seem to be a common problem but I hope someone can suggest what might be causing it please?