We all know, and "love", this meaningful message from somewhere inside of a system. Luckily I can say, in my last projects I became able to almost eliminate those failures - without a 100% unit test code coverage. (Those outside there who say, 100% code coverage by unit tests is a must must, please don't flame me. I'm a big fan of well tested software, but I guess I'm not yet ready for 100% coverage ;-).)
My solution for this "old enemy" was much easier than some might think..
Object reference not set to an instance of an object
florianreischl.blogspot.com