In some apps that I run as administrator in Vista, scrolling with the touchpad only works in one direction (depending on the app). Scrolling with an external mouse works just fine. When not run as admin, touchpad scrolling also works just fine.
Apps that I've confirmed the problem with: MS Visual Studio 2005 (Team Edition), XEmacs
System: Vista x64 Home Premium, Synaptics touchpad (most recent drivers installed for my notebook, v10.1.8)