Linux server crushes after some time

I am using GameServerManagers script on Ubuntu 14.04 and by adding this line:

Code:

export LD_LIBRARY_PATH=/PATH/TO/SERVER/FILES:/PATH/TO/SERVER/FILES/RustDedicated_Data/Plugins/x86_64:{$LD_LIBRARY_PATH} ;

got it working BUT problem is that it crushes for no reason with some Sound error after unknown time of period (random?)?!

Code:

Function SoundManager* GetSoundManager() may only be called from main thread!
Function SoundHandle SoundManager::IntegrateFMODSound(SoundHandle::Instance*, const StreamedResource&, UInt32, int, SoundHandleShared::LoadState) may only be called from main thread!
Function SoundHandle::~SoundHandle() may only be called from main thread!
Function void SoundHandle::Instance::ReleaseIfNotReferenced() may only be called from main thread!

Any ideas whats wrong?!