If you find lines like those in your OpenVPN log:
NETSH: C:\Windows\system32\netsh.exe interface ipv6 set address Local Area NetworkERROR: netsh command failed: returned error code 1
This error is really frequent on Windows and seem to happen because of a OpenVPN problem with netsh.exe and IPv6.
To fix it, rename your network connection to avoid spaces, for example "Local Area Network" to "lan".