VirtualBox
As it turns out, OpenVPN and Oracle VirtualBox on the same computer just doesn't work. Uninstalling VirtualBox would make it possible to connect to my VPN server.
However, I then encountered another issue...
TUN/TAP Driver
If the VPN connection dropped, like due to an unstable wifi link, I could never get it to work after it had reconnected.
After rebooting it would work fine though, so after a bit of fiddling I came up with a workaround. Before reconnecting to the VPN server I have to disable and then re-enable the TUN/TAP network driver. Go figure...
Software Used
- Windows 7 64 bit professional edition
- VirtualBox 4.0.10 and 4.1.0
- OpenVPN 2.2.1