After looking around I found out that for some reason the icon files of the application not picked were located in the folder c:\users\publicdesktop\... rather than in the allocated folder for that desktop which is c:\users\MyName\desktop. Don’t know how this happened but moving the icons into the correct folder worked.

Running Dexpot 1.6, Win 7 Prof, UAC deactivated, not as admin. Initial installation finds installed programs and associated icons. New installations are not registered. The same happens when running as admin.