Have you protected your cert/key with a password ?
If so you may need to specify --
askpass in the config file .. Although, the
README.md says the GUI should do this automatically.
The required dependencies are checked when you install OpenVPN, if they are not found the installer should display a message about it. When you do an install there is a log file displayed on screen which will read:
Checking .NET Framework version...
.NET Framework 4.0 Full found, no need to install.
Proceeding with remainder of installation.
Completed
that is if .NET is installed ..
You could try re-installing ..