After the 1994 elections, the first to feature participation by all South Africans (not just the whites), the military quickly turned into another form of patronage. The word came down that the military was there to provide jobs for political loyalists of the party in power. These men could be dismissed only if they committed a serious crime (rape, murder, kidnapping) and were otherwise untouchable and increasingly undisciplined. Eventually most of the troops are too old, too sick or too undisciplined to be effective soldiers. The government gets away with this because South African has no neighbors that pose a military threat.
They also have an article on Nigeria's problem with corruption
On the other hand, they discuss the good work of Uganda, Kenya, and Burundi troops who work with the African Union peacekeepers HERE.