I finally noticed the pattern to this problem. Not surprisingly, it is related to User Account Control. (I am using Win 7/64, but it almost certainly applies to Vista as well. It was not a problem in Win XP.)
In every case the offending program requires approval of the UAC message "Do you want to allow the following program to make changes to this computer?" The problem disappears if UAC is turned off (set to "Never notify"), which confirms that it is associated with UAC.
1. Can other users confirm this pattern?
2. Does anyone know how to run the offending programs without requiring this UAC approval every time? I have experienced it with CCleaner, Revo Uninstaller, and Paragon Backup & Recovery, and it is reasonable that programs of that type would require higher security permission. But I also have the problem with two text-based database programs which are no security threat at all. In any case, I would like to permanently approve these programs so they can run without specific UAC approval. (I am using an Administrator account.) Thanks.