Is this maybe it?

Anyway you want to uninstall "wacom-dkms".

What is happening is the dkms (dynamic kernel module support) implementation of wacom.ko from the PPA is probably an older wacom.ko that does not support your tablet. If I knew the PPA I could find out the version. And what it is doing is overwriting any wacom.ko you compile and install that does support your tablet with the non-working wacom.ko from the dkms directory. Which is why you can't get it to work. Follow?