I had this problem with mine at one point, how I resolved it, could have been either one (or a combination of) the following...
Find the Tablet Cfg Menu (usually it's somewhere on your taskbar) and UNCHECK the "Supports Digital Ink" box.
or
Download the latest driver update from the Ugee website
Link here:
http://www.ugee.net/download/index/p/1.html (< page1 of 2)
Or perhaps you need to click on Edit>Preferences>Input Controllers and set-up the tablet from there (not sure about this though as mine is working fine and it's not even included in the "Active Controllers" list!!)
Hope you can resolve the problem, good luck!