what mistake does Freddie Widgeon make when he meets an 'old friend' in Cannes in The Most of P.G. Wodehouse?

While in France Freddie runs into a man who claims to be an old school chum. This man suggests that he and Freddie meet for a meal, which Freddie mistakes as the French word 'mille' meaning one thousand. Freddie racks his brains trying to raise the money.