Do you refer to the “Universal Access Control”?
Windows has a security feature that prevents applications to send input (through the touch injection API) to application windows with higher permissions. For example the UAC, device/services manager, and probably the lockscreen as well.
I tried to avoid this by requiring TouchInjector to be executed with maximal permissions. Maybe this was not enough for some reason.
As my touch table is located at my parents place, I can’t really debug this until the weekend.
Please try to control more sensitive system applications (services manager..), run TouchInjector with elevated permissions. (Make sure you are using a administrator account as well.)
EDIT: Please note that if the user is logged off, TouchInjector does not run. Only Windows services can run withouth a user being logged-in..