About 2 years ago, when it came to light these bomb detectors were totally fake, the Thai government, who has bought a whole bunch of these came out insisting they were real and worked.
My hunch is there are no "real" portable bomb detectors (other than a trained dog), and government middle managers under pressure to buy bomb detectors bought the only thing on the market claiming to do that regardless of whether it worked or not. They knew it didn't work, but the politicians further up the chain didn't care, they just wanted to be able to say they'd purchased bomb detectors and people would be safe.
Alternately, maybe James was just really good at structuring kickbacks and bribes to the decision makers. Its not like Thailand, Iraq or Kenya's governments are corruption free.