I was getting this error on my openvpn server : read UDPv4 [EHOSTUNREACH]: No route to host (code=113)
it seemed to be a network problem , but after a lot of work I found out it is because the time and date of the client side was out dated !
if you are having the same problem please read this post : http://www.adminsehow.com/2009/06/how-to-synchronize-linux-time-daily/