This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
What could cause a NullPointerException? allowedFile is a File object, and as you can see it is NOT null. Besides, if it was, the AllowedProperty constructor throws a NullPointerException with a custom message:
The stack trace says the error occurs in the AllowedProperty constructor at line 53. Show us that whole constructor and point out which is line 53 (the first line in a file is line 1) and I will tell you exactly what the problem is.