plasma(5728) KWallet::Wallet::openWallet: Pass a valid window to KWallet::Wallet::openWallet().
plasma: symbol lookup error: /usr/lib/kde4/plasma_applet_showdesktop.so: undefined symbol: _ZN6Plasma14ToolTipManager4selfEv
plasma(5727): Communication problem with "plasma" , it probably crashed.
Error message was: "org.freedesktop.DBus.Error.NoReply" : " "Message did not receive a reply (timeout by message bus)" "
Something seemed to be wrong with the plasmoid "Show Desktop". Only problem is - it's pretty hard to remove a plasmoid when plasma won't even start. With a bit of help from Google though, and a few bash commands, I found the configuration file that plasma uses to configure the applets:
david@suse:> kwrite ~/.kde4/share/config/plasma-appletsrc
In this file, I simply had to search for the text "plugin=showdesktop", remove the configuration section associated with this, and start plasma again.
This is a simple way to remove a plasmoid (plasma applet/widget) without starting plasma.