Random server crashes - Core dumped

Hello,
I’ve recently changed the machine I’m using to host a server (dedi).

I’m currently setting it up but I’ve ran into trouble. Totally random the server crashes with the reason:

I’m the only player on the server and using the same addons as on my own server without issues.

At start, I thought it might help to change OS, so I changed to Ubuntu 14.x from Debian Wheezy, where the above error also occured.
No change. I don’t really know what else there is to do?

[editline]23rd November 2014[/editline]

Adding -debug to the startup line gives the following issue:

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