johannesburg south africa african national congress say saturday executive committee decide anc officials bar court attend leadership conference weekend would take part vote special committee meet urgent deal three court case give yesterday structure nullify vote delegate conference anc secretary general gwede mantashe tell reporters want contaminate conference ... vote matter court rule senior officials two provinces see back nkosazana dlamini-zuma party leader illegally elect therefore could attend spark rally rand investors bet decision favor rival deputy president cyril ramaphosa south africa 's anc say party officials bar court vote conference