...don't use KDE? *cough*, sorry.
As far as I know FreeBSD such inconsitencies mostly happen when system and userland are not on a consistent level, and mostly can be solved by achieve a consistent system.
Which in detail means:
Do a freebsd-update, then a pkg update.
If this does not help, wait a couple of days, and try a pkg udate again.
When recent versions are freshly released, it may take one, two, sometimes four days, until all packages are compiled and provided for the "same level of versions".
If this does not help, you may try a pkg remove kde (don't know the actual package name), and try to compile it from ports yourself (and of course your themes, if those come not automatically as a dependency).
