I had changed my installer to override the Windows Installer program list.
But when uninstalling though Windows programs list it is not showing my theme and buttons icons in some dialogs, link that:
Can you please check if the "Always (install, uninstall and maintenance)" option is checked for the Enhanced User Interface ? You can check this by going in "Themes" page from the "Requiremenets" group, under "Settings" tab.
If this does not help, can you please give me more details about your scenario ?