Why did the old man describe the bet as 'cursed'?

The old man describes the bet as cursed because it will soon be time for the debt to come due, and it looks as if he will lose the bet. Thus, he will be ruined financially.

Desperate gambling on the Stock Exchange, wild speculation and the excitability whic h he could not get over even in advancing years, had by degrees led to the decline of his fortune and the proud, fearless, self-confident millionaire had become a banker of middling rank, trembling at every rise and fall in his investments. "Cursed bet!" muttered the old man, clutching his head in despair "Why didn't the man die? He is only forty now. He will take my last penny from me, he will marry, will enjoy life, will gamble on the Exchange; while I shall look at him with envy like a beggar, and hear from him every day the same sentence: 'I am indebted to you for the happiness of my life, let me help you!' No, it is too much! The one means of being saved from bankruptcy and disgrace is the death of that man!"