I was going to ask if you'd post the contents of dolphinrc, but I see you reinstalled. Glad you got it working.
BTW, there's not a Kubuntu 10.20. Ubuntu release numbers get the numbers like this.
eg. Ubuntu 12.04
12= 2012 and 04 = month, April
Ubuntu and other varieties, Kubuntu, are released twice a year, every April and October, so you get a list like this.
You can see each year, an Ubuntu release comes out twice a year or every six months always on April and October though sometimes the release may be delayed if it's not ready by that time.
Another note: The difference between 12.04 and 12.04.1 is that a problem was discovered in 12.04, so Ubuntu maintainers fixed it and released the same 12.04 with the fix as 12.04.1
Some versions of Ubuntu/Kubuntu are known as LTS (Long Term Support) and will be supported for 4 years after their release.
If you're using an older version of Kubuntu just wanting to use KDE 3.5 instead of KDE 4.x, I suggest using this instead.
It is a port of KDE3.5 that gets updates and is still maintained.
Because KDE 3.5 is no longer supported, you will not get upgrades to it except maybe security backports in an LTS version of Kubuntu using it.
You can get a good distro that includes Trinity Desktop already in it.
(Live CD has an installer and Fedora is a good newbie friendly distro like Ubuntu).
Or you can read on their website on how to install it into your own distro.
You should very rarely have to reinstall or reboot Linux to fix something. It's not windows, and by troubleshooting the problem, you gain skills and experience.