Delayed for two nights at the Uganda-Kenya border, Kuria woke up unsure if he would spend a third night in Malaba, the seedy Ugandan border town. But his papers cleared customs at the last minute and his company rushed in a spare part to make his truck roadworthy again. So off he went in the afternoon.

By day's end, Kuria had traveled only 110 miles and had been shaken down by customs agents who accused him of carrying too much diesel fuel into Uganda. But the Kenyan driver was grateful his delays at the border were relatively brief, by African standards.

David Koech, who works for the firm shipping food, takes a part from his truck to fix the relief truck.

View more photos from Day 6 Watch a video tour down the Nile

"I wanted to get moving again," said Kuria, 56, whose truck is carrying grain donated by the U.S. Agency for International Development to war victims in Sudan.

The life of a truck driver in Africa is filled with delays - bureaucratic screw-ups, encounters with mercenary authorities and mechanical problems. For drivers with little cash or contact with the home office, delays can stretch into weeks.

Thomas Masila, a Kenyan driver who works for the same company that employs Kuria, M.A. Bayusuf & Sons Ltd., left the Indian Ocean city of Mombasa on March 28 with a load of 8,000 gallons of fuel oil for the landlocked nation of Burundi. He has spent more than half the last month stuck at three different international border crossings.

"You know there are so many documents for each country, you can't prepare for it ahead of time," Masila said, shrugging.

Masila, whose empty fuel truck was parked at the border yesterday on its way back to Mombasa, said he spent five days at the border earlier this month when Uganda Revenue Authority officials demanded he produce a "transit goods license," which allows a truck to carry goods through Uganda.

On Tuesday, Kuria and another Bayusuf driver who is hauling sorghum to Sudan arrived at the Ugandan border and were also asked for a transit goods license. Kuria said he never heard of such a document - and he had been through the same border two months ago.

It turned out that Uganda has required a transit goods license for years. But nobody ever got them. Clearing agents who process the paperwork for transporters said it was cheaper to bribe officials to let the goods in without the transit license than to buy the license itself.

The rules changed recently because of pressure on Uganda by international lending agencies to clean up corruption. "Now, suddenly, they want transit goods licenses," said one clearing agent.

On Wednesday, Bayusuf faxed the vehicle's registration documents to Ugandan authorities and wired the $230 annual license fee to the post office on the Kenyan side of the border. Kuria collected the money in Kenya and carried it across the border to Uganda.

In the meantime, Kuria and his son James, who is employed as his assistant, discovered another problem. On Tuesday, Kuria damaged a brake drum on the rear of the 40-foot trailer. A Bayusuf mechanic was called in from Eldoret, Kenya, to repair the brake.

The mechanic found that a bearing on the rear wheel was also damaged.

The home office instructed Kuria to take a bearing from another truck at the border until the company could ship a new one from Mombasa on an overnight bus.

Yesterday, the new bearing arrived, and the mechanic replaced it in less than an hour.

Kuria drove less than an hour out of Malaba before he ran into trouble with the Uganda Revenue Authority again. Photographer Michael S. Wirtz and I had left in a separate vehicle to explore the source of the Nile, so Kuria was on his own.

At a roadblock near Buwayo, customs officials waved Kuria over to the side of the road. Kuria was asked to sign a declaration stating how much diesel he had brought into the country. Uganda tries to limit the fuel that comes in because drivers often sell the excess on the black market; diesel costs 30 percent more in Uganda than in Kenya.

Kuria stated he carried the legal limit of 800 liters (about 210 gallons) for a truck traveling to the Sudan border. The customs officials accused him of understating the amount and offered to let him go for a payment of $40 or 100 liters of diesel.

They settled for $10 and 20 liters.

When we caught up with Kuria an hour later, he was still rattled by having to pay the bribe. The truth is, he did fib about how much fuel he carried - he had 1,000 liters of diesel. He said he has no intention of selling it. He just wants to be sure he has enough to get home.

"If you tell the truth, you lose," said Kuria. "In Africa, there's no telling the truth, because all that man wants is the money. It's all corruption."

Along the lush northern shore of Lake Victoria, the Trans-Africa Highway is battered but manageable as it passes through gently rolling land, broken occasionally by small hills. In the evening light, the land is a riot of intense green.

The country is more densely populated here, with the shoulders of the highway filled by pedestrians balancing bunches of bananas, firewood and water jugs on their heads.

At Jinja, Uganda's second-largest city, the highway crosses the Nile atop the Owen Falls Dam, an ugly brownish mass bristling with transformers and power lines. The dam is at the source of the world's longest river, whose discovery obsessed 19th-century explorers.

Here Lake Victoria empties into the Nile, beginning a 4,000-mile journey to the Mediterranean. In 1862, British explorer John Hanning Speke came across the falls, which he described "as a sight that attracted one for hours." Now it deserves about five minutes.

In 1954, the British government built a dam atop the falls. They're gone forever. There's a small park upstream, dominated by a huge ad for Bell Lager, "the source of Great Refreshment."

A guide, James Bakambe, stood on the bank, touting a tour boat supposed to arrive in two minutes. He says the river is "136 feet deep, or 70 meters." It appears to be neither; it looks no deeper than the Schuylkill.

After 20 minutes, the boat has not arrived and Bakambe is staring upstream. It's hard to believe that explorers were willing to die to find this spot.