Stupid, I know!
Was going to add a repository in order to get and install XBMC but instead I sadly erased the whole sourceslist. And I don't have a backup.
I have a new fresh Mint 5 KDE up and running so if someone PLEASE could post a new "/etc/apt/sourceslist" I will be forever grateful.
Apart from this the new Mint 5 KDE really rocks
There is just that irritating problem with playing ape+cuesheet files left so solve. ?