I wanted to connect to mrfreake's server: DMPServers.chickenkiller.com
I couldn't because it came up with: Connection error: EndRead failure, Connection reset by peer

Which of them? And was your DMP client up-to-date?

EDIT:

<DP110> [20:42:24][INFO] : Client manni01  failed to handshake: Protocol mismatch
<DP110> [20:42:24][INFO] : Client manni01  disconnected, sent HANDSHAKE REPLY (Protocol mismatch) to endpoint ***.***.***.***

Which means that your DMP is outdated. Download DMPUpdater, place it on your KSP folder (where the KSP.exe is located) and run it.

The file i downloaded is confusing with many .cs and .csproj and .sln which are confusing. I don't know which one to use wine on. Is there a mac version?

Uh, you've downloaded the source. You can find the download here: http://chrisand.no-ip.info:82/dmp/

This is still a bug, it should have clearly stated that your version was incorrect for the server.