Hi! I’ve consulted our Pichon developer about your question. I will quote an answer here to avoid technical misunderstandings:
This error occurs because of a bad installer and an old version of the .NET Framework. We will release the new Pichon on .NET5 soon, and it will not require to install the .NET Framework. It will fix the launch via Wine. We will release it this way till the end of February, with a 50% chance till the end of January. When switching to .NET5, the color picker and a couple of other things broke so we will need to make them from scratch, and this will take time.
To check if this scheme works - so that you could already wait or not wait for the update - try installing Lunacy (it has already been transferred to .NET5) via Wine. If the installation succeeds and Lunacy starts well, there will be no problems with Pichon either. If Lunacy does not start, then we can say that the problem will be resolved around the end of spring.
I hope this will help! Let me know if this answers your question, or if you have any additional ones.