This is a known problem with the RC and will be fixed by the final release. It looks like a bug in 'mintinstall' rather than a problem with KDE itself and was seen in the Main Edition of Linux Mint 12 early on as well although it seems to be fixed there with the latest updates. LM 12 KDE should have the fix in shortly I would imagine.
"Humph. Choice, it is the quintessential Linux delusion, simultaneously the source of it's greatest strength, and it's greatest weakness." (All apologies to The Architect)