I have had the same problems. When I upgraded to vfp8 all my icons were lost too. I went around & round with installshield support, they were no help at all. Finally someone here gave me a workaround that works for me.
Make sure your icons are correct. They must contain a 16x16 icon as well as the standard desktop 32x32 icon in order to display in the add/remove programs of windows. There are several tools around for doing this.
Remove any and all icon designations from the installshield program. They would not work for me. Even the shortcut icons as well as the display icons. Just leave those fields blank.
Attach the icon file that contains all your desired graphics sizes to your application exe or app. I use the resource hacker for this. Not vfp.
http://www.users.on.net/johnson/resourcehacker/My icons display properly on all shortcuts, on the add/remove program list in the control panel when I use this method.
hope this helps, steve