ksynaptics says : No usable driver has been found! Either your driver is not correctly installed or you are using a wrong version. You need at least driver version 0.14.4! information: libsynaptics 0.14.6c-r1 using driver version 0.15.2
the project says its abandoned upstream. When i changed the dependency in the ebuild to DEPEND="x11-drivers/xf86-input-synaptics" it will install fine, but it wont run. Same message as you get. Probably an easy fix somewhere in the code to just change the checking of driver version since that changed in the new synaptic packages. if someone has the time to figure it out and patch it.
Friendly note from kde devs: if it is not working patch it, or at the start of next month we will rite it from the tree as dead. :]
*** This bug has been marked as a duplicate of bug 236924 ***