Africa's problems are largely due to colonialism.
Arguing otherwise is arguing from a position of extreme ignorance.
You cannot expect culture(s) to develop when they are subjugated, slaved out, forced off their land, killed, oppressed and excluded from any meaningful participation in government.
And the effects of these actions take longer than a generation or two to overcome.
Take South Africa for example, 18 years since our first democratic elections and the advances we have made are incredible. Even so, the systemic results of Apartheid are still very apparent and make it very difficult for the poor to make an improvement in their lives. It's happening, but in spite of, not due to, the influence of "Western Culture".
This of course leads to a new issue which is, what exactly is defined as "Western Culture". Is an African Politician driving the latest BMW, wearing an Armani suit and talking on his iPhone part of Western Culture or African Culture? Is a traditional healer that uses a Facebook page to reach customers part of African culture or Western culture? Is a white South African working for a black South African part of Western Culture or African Culture?
You can't claim one is superior to the other if you cannot differentiate between them.
And finally, to underscore the theme in this thread that Africa is an amazingly diverse place I will layout some of this African's current problems:
(1) Sitting at work not really wanting to see a Masters Student and discuss their research topic of Virtual Worlds and Team building. (Black African student btw).
(2) Wondering what to do with a colleague of his, hailing from Eritriea, who doesn't always do his work.
(3) Trying to figure out if he has time to play the Diablo III open beta this weekend.
I'm wondering if the "superior" Westen culture could help me with any of those?