Could this be the same issue as when I run cgminer after having a long pause? cgminer makes bin-files (like scrypt130302Pitcairnglg2tc5120w256l4.bin) which it works with, and I think it saves info on block etc it is currently processing. If I too long of a timeout before starting cgminer again, it will sometimes crash or fail - I think becuase it is trying to handle information that is no longer valid.
Or I could be way off, and this has all been for nothing