The fact that Annan 'did nothing' (which I don't believe, I think he was likely involved) is exactly the problem. He was charged with ensuring the money was used to feed the Iraqi people. Instead it buit palaces, bought yachts, funded terrorism and WMD programs. Meanwhile, the people the program was supposed to help starved and suffered from lack of medical supplies. And Annan, the guy in charge, to quote Tommy Oliphant, "did nothing."
I'd love to have a look at the "nothing" that's in Kofi's Swiss bank account.