I bought my Wacom Bamboo Fun tablet more than a year ago. And from that time until now, it has never worked with Windows applications built with GTK+ like Inkscape and GIMP. The mouse cursor would freeze up the moment it entered the application window!
There seems to be some fixes in GTK+ now to ameliorate this situation. To fix this problem for Inkscape:
Update Inkscape to the latest version.
Download GTK+ 2.18 or later for Windows. Unzip the setup file.
C:\Program Files\Inkscape with the same file from GTK+.
The Wacom Bamboo Fun mouse and pen should work fine with Inkscape now. Sadly, this does not fix GIMP to work with Bamboo Fun! ☹
Update: John Burnett has suggested an alternate solution that should probably work. Please see the comments below.