stowite:
You are both missing the point of my original post! The third party library seems to be failing because it has very time critical code and even though my interrupt handlers have been pared down to the very minimum the fact that I am handling about 5000 per second seems to cause the problem with the library.
I don't see how we can be missing the point when you have never said what you are actually trying to do.
Post your code so that we have the same information in front of us as you have.
Maybe the code (library) that you would like to include in your sketch just isn't fast enough for 5000 per second?
...R