But no worry, I read it a couple of times today on Frosty discord channel that for someone Frosty showes an error. In my case frosty loads About 15 minutes to be Ready to go. I know this does not helps you now, but I already watch the discord for frosty what Galaxyman write to give us a solution. If I get a answer I will post it here for all of us, ok?
Is there an issue connected with your Windows language pack, try to run Frosty with an OS with ENG language.
In the fact you are not able to run the CM19 because the same issue connected with .NET Framework language installed in the client.
Try to install every Net framework with all languages inside like the full SDK.
Link is here, download the required: https://dotnet.microsoft.com/download/dotnet-framework