Bug#463772: gimp: enabled 'configured mouse' (insted of core pointer) brings an error

[Cedric Laczny]

I experienced a similar problem. I don't know about error messages as I 
started GIMP directly and not via a console.
But I had a working stylus and eraser but when using to mouse, I got no effect 
on the image, no matter what drawing tool I used.
I figured out that disabling _all_ extended input devices made my mouse work 
again, although the stylus was now no longer pressure sensitive (seems 
reasonable).
But when I now enabled the stylus and eraser again (set to Mode: Screen) 
everything worked as expected! The mouse resulted in effects as well as the 
stylus/eraser including pressure sensitivity.
However, when I changed the characteristics of the stylus using wacomcpl, I 
ran into the same problem again. It could be fixed with the disable + enable 
procedure. So apparently, when using wacomcpl, it must mix up something in 
the configuration so that GIMP needs to "reset" the extended input devices.

Hope this helps.