WASHINGTON  - A US federal court threw out Tuesday the conviction of Osama bin Laden's former driver, who was jailed at Guantanamo, saying material support for terrorism does not constitute a war crime. While Salim Hamdan has already been freed, the Yemeni's appeal in civilian court could have ramifications for other suspects as "material support for terrorism" is a common charge against detainees at the US prison camp in Cuba. A three-judge bench at the US Court of Appeals in Washington said that a law that listed material support for terrorism as a war crime - approved in 2006 in response to Hamdan's case - could not apply to him retroactively.