@maple leaf, I think Ivo is more talking about a lack of critical thought than a lack of knowledge. Often, just a little bit of knowledge is more dangerous than a complete lack of knowledge...
That said, I think I'm more in agreement with jadayne than Sic's argument. A lack of critical thought is definitely a significant source of "evil", but I would not say it is the root of all evil. I hate to use the word evil though, because I don't consider myself a moralist, but more a utilitarian.
I would say most of the world's problems and suffering comes from the simple fact that there are finite resources but a seemingly endless desire and an evolutionary imperative to reproduce beyond the carrying capacity. Competition in a heterogeneous environment naturally produces winners and losers, wealth and poverty, health and illness, etc. There will always be a conflict of interest and drive for a larger piece of a finite pie. It may be deemed immoral, but practically speaking competition also is rigorously efficient and pushes our progress further and faster than any stagnant environment. Our best chance at more or less indefinite survival lies with maintaining a competitive environment. It's a sad truth, but all utopias will inevitably fall to it's more ambitious neighbour.