We've determined the problem.  It was just one of those things that happen when you are working.  He's more worried about it than I am.

I have a philosophy that a lot of folks either don't understand or just know how to apply themselves.  I rarely lay blame.  Look at the situation, figure out what happened, don't do it again, and fix it if possible.

Now if you do it 2-3 times we might start talking about blame.  But stuff just happens.