Earlier I have written how I configured my Raspberry Pi configured for media playback. Then on comments I write how XBMC-Elisa-Viihde-plugin started to fail and I could not solve the issues (normal update, plugin uninstall/install and even full reinstall did not work).
Now I finally have success with my Raspberry Pi media player. Reinstalling the newest version of whole system to a new SD card fixed the issues (installation done as I told in Raspberry Pi configured for media playback posting). Now the system works well with Elisa Viihde and YouTube.
It seems that something was wring on my installation and/or some earlier RasbMC installation, something that normal updating did not solve… and an earlier attempt to reinstall. Anyways now everything works again and I ma happy with that. I don’t think it is worth of time to check what exactly went wrong.