I will get modded to hell for this but as someone who is of Haitian decent and has family there right now the true cause of the corruption is bribery from states, corporations and even the IMF. The rice riots are a perfect example
When the IMF loaned much needed money to Haiti it came with requirements that they open the country to "Free Trade" (Many Haitian politicians got their palms greased in this deal then left the country) when that happened American corporations flooded the market with cheap food which sounds great at first but when you consider the fact that the majority of the population made its living as farmers it doesn't sound so great. Farmers either lost their businesses or were forced into what amounted to virtual slavery for corporations who conveniently had money to lend them in their hour of need as long as they grew the crops (which were largely inedible) that the corporations wanted. Now you say "It all worked out great the farmers now have jobs, everything worked out for all parties!"
WRONG, the corporations paid the farmers pathetic prices for their crops because they were desperate and with agriculture being the only means of earning a living everyone in the country turned to farming, they tore down every tree in site in order to use every bit of land so they could earn enough just to survive. The worst part about this happened much later, with large areas of land in Haiti virtually treeless due to over-farming, Haiti got pounded by hurricanes three years in a row. With no trees to hold the ground into place when there was flooding large areas of land simply washed away killing thousands.
If the world really wants to help Haiti we need to do three things....
1.) Forgive much of Haiti's debt
2.) Lift all of the ridiculous restrictions that came with the debt
3.) Restrict foreign corporations and states from meddling in the country's politics