A company loses money when its costs exceed its revenues. If Apple has to pay Warner Brothers a sum contractually specified in dollars for each copy of "Pump Up the Volume" that it sells, it could easily lose money if the rouble falls more quickly than they can adjust prices.

That's a small(ish) percentage of Apple's overall sales, even in the US where they have the most digital products to sell.

Hardware (iPhone, iPad, Mac, in that order) make up the vast majority of Apple's sales revenue.