Several weeks ago, on both my computers (ThinkPad X1 running Kubuntu Precise, ThinkPad T520 running Kubuntu Oneiric), KolourPaint began exhibiting a problem. It looks like some of the resources it would use for icons have gone missing:

I've been hoping that an update might fix this, but apparently not. Both oxygen-icon-theme and oxygen-icon-theme-complete are installed. I've tried deleting ~/.kde/share/config/kolourpaintrc, no change. Anyone have any ideas what to check?

Outside KDE, please try removing /var/tmp/kdecache-$USER/ and make sure your / and /home directories have plenty of free space.

Thank you, however deleting the files in /var/tmp didn't work. Also, / is is 30 GiB, of which 4 GiB is used; /home is 80 GiB, of which 18 GiB is used.

I've placed the output of strace kolourpaint at https://gist.github.com/2389026 if that's of any help.

If you open System Settings > Application Appearance > Icons, is "Oxygen" selected?

Well, uh, sort of

I've been using Oxygen-Transparent from šumski's KDE Goodies PPA (https://launchpad.net/~hrvojes/+archive/kde-goodies). When I switched to regular Oxygen, two of the toolbar icons reappeared. I logged out of KDE and deleted the caches in /var/tmp again. And then, after logging back in, all of KolourPaint's icons returned. Certainly seems like Oxygen-Transparent is the culprit...I'll have to open up the .debs and compare the two themes.

For anyone trying to solve this problem in 2016, open a terminal and type in the following:

sudo apt-get install kde-runtime
Press Enter

Problem solved, at least in my case