This is an example of how un-initialized variables crash PHP. The string in the class will point to garbage at the start, which will then be attempted to be copied to PHP. The crash occurs in strlen as it cannot find the (non-existent) string terminator. Ideas on fixing this problem are welcome!. Until then, uncomment the '-nosync' flag in the Makefile to fix the problem. This does mean having to use the set/get functions directly in your PHP code if you have the same problem.