Kernel need fixing "I have no idea what does it mean"
I'm so totally stupid when it comes to managing servers... "why do I have one then"
Well It is just to help others store and share files.The hosting company sent me an email saying:
A few things to remember. First, you need to fix your kernel right away because it will go down again for sure. The two reboots within a 24 hours period is quite unusual since an experience admin should be able to run a dianostic to determine the problem.
Also, have you consider using your APC rebooter? We'll set it up free of charge and you'll never need to call us for this type of issue. Your server has been rebooted and SSH is now available. Again, your server will go down again unless the kernel is fixed.
Ok... first thing I have no clue what they are talking about
how to fix this kernel.. and why is it a problem ... I'm for sure not EXPERIENCE admin 
I put the server out of service until I know the answer... I've searched in this forum for "kernel" but still did not understand a thing
Note: I'm managing the server with Webmin.... how can I find the problem and fix it thru Webmin ?
Your help is reaaaaaaaaaaally appreciated.... not only from me but from all of those using the server to share files
