Hi Omega,
I haven’t been able to reproduce the crash or the errors that you mentioned, however ‘Accessed None’ errors in an empty Construction Script is something that we have been investigating for some time. They are generally cosmetic and will not cause any issues with your project (except for making it a bit harder to debug). It is JIRA UE-3412 in our tracking software.
What concerns me most is the crash. Could you provide a small test project with the crash error for us to investigate further?