It is a "Catch 22". He cannot take the course because he does not have time. So he cannot learn how to manage time better, so that he would have the time. A Catch 22 is a pair of circumstances that each set up a blocking of a solution to a situation, and together completely close the door on any solution. This is a slightly humorous way of saying "I am really busy. I have a lot of things to do. Maybe I could do better, but I am too busy to figure out how it would be possible."