I had that it had an infinite loop if the correct accountNumber wasnt found. That is if
IF accountFile.accountNumber = accountNumber
Is never met, than the flag will never be set to true and it will keep looping through forever. I could be wrong as though :p
You shouldnt really set yourself limits on what you write... If you know a lot of information then put a lot of information down, you can only get more marks. I've never heard about the BOS saying it should be 2 lines to a mark, it seems rediculous that they would say that.