Google search didnt help.
But it did turn up a report of the same problem:http://tehparadox.com/forum/f85/sketchbook-pro-windows-8-a-3941689/
What you can try is find the Sketchbook Pro application program (usually a .exe file) and located in the Program Files folder.
Right mouse click and choose Properties, and use the Compatibility Tab.
Try using Comparability Mode options for Win7 and maybe Vista or WinXP.
Also choose Run this program as Administrator option.