Without seeing your config or log I guess that openvpn first starts but then crashes when using "Start" button.

Openvpn crashes if you have set verb 4 or higher in configuration file. Test button sets verb to 3 but start button uses what ever is set in configuration. Maybe I should address this problem in the next version.

If verb values isn't your problem maybe you could post you configuration file somewhere with private data anonymised (ip addresses etc)