I can't exactly figure out why or when, but my USB drive icon, which used to be the PortableApps platform icon, suddenly disappeared. My Autorun value is
StartPortableApps.exe looks fine until I right-click and go to Properties. The icon is not shown and I only get a Windows Vista dummy icon (a page with a window on it)
I'm running Windows Vista. Everything else with PortableApps works fine, but my icons are missing.