nothing wrong with diffing the changes and see if theres a clue, but to solve this one really needs to find the underlying cause no matter what. changes can just hide bugs or make them more or less likely to appear. can anyone provide at least a stacktrace or process snapshot of the crashed dns processes? from that you try to build a theory of what might be going wrong by thinking really really hard... (the thinking should be directly proportional to the time it takes to reproduce the bug) and then you work on how to prove that theory. just changing stuff without knowing what exactly was the problem with the old code is sometimes tempting, but wrong and dangerous.
-- cinap