Multiple programs can use Gemini.NET ASCOM driver at the same time. It's an ASCOM hub.
If you are having problems connecting from multiple programs, it's likely that you have different user settings for one or more of the programs. If any of the programs are being run 'As Administrator', you'll need to make sure that all of them run that way. Mixed 'As Administrator' programs and 'as regular user' programs will not work together.