I suggest you to remove kernel and reinstall it with Software Center.
To remove it:
- start NethServer with an old kernel
 - remove kernel (e.g. 
yum remove kernel-3.10.0-229.el7.x86_64) - download software updates
 
I suggest you to remove kernel and reinstall it with Software Center.
To remove it:
yum remove kernel-3.10.0-229.el7.x86_64)