Harbinger and Spectral Enderman crash

[EvilWiz]

So we have a dedicated server running on a friends unix server and keeps getting java time out errors when trying to connect to the server. Whats happening is that when any one of us gets attacked by a Harbinger and if it summons a Spectral Enderman it will instantly crash the server and none can get back on. Last time he was able to just restart the server and that fixed it but this time its not working. Any thoughts? Or would he have to go through and try to find the crash report and the bad thing to delete per the crash post?

Is there also anyway to just turn off that one monster in the game till that bug is fixed? Its running Hexxit 1.0.7 since its set on Recommended.