Royal Caribbean Cruises Ltd. on Monday reported a fourth quarter loss attributed to the company's massive impairment charge for its Pullmantur Cruises line. The world's second-largest cruise line operator (NYSE: RCL) said its profits were at a loss of $392.8 million on revenue of $1.8 billion for the fourth quarter. Profits were down from $36.6 million, but total revenue was up from $1.78 billion in the same period last year. The Miami-based company said it recorded a total impairment charge of…