When you install OpenVPN on a machine, you get the following message:
"Cannot load certificate file C:\Program Files (x86)\OpenVPN\easy-rsa\keys"
Please check that the machine is 64 bit, if not, there will not be a Program Files (x86)\OpenVPN but there will be a Program Files\OpenVPN
The simplest way is to create a Program Files (x86)\OpenVPN folder and copy the files into it. That way both 64 and 86 machines will be consistent across your office network.
Alternately you can edit the configueration files as described here