In the header of the error message, there is a short instruction what you need to do with it. You are suggested to save it and send it to tech.support@turris.cz together with a short description that led to the error.
In the Foris error, there might be sensitive data, so you shouldn’t put it here. Forum is not meant to be bug tracker and you’re advised to follow our article for Error reporting.
Also, your message here is too long. While you’re writing a post here, there are a few buttons. Some of those are a spoiler, preformatted text, which you can use. The better one is [code][/code], which would be really useful for you.
However, I asked one of our developers to look at your error message, and we will see if there is anything that could be done about that.