What are all these errors?

[koberulz]

They happen intermittently with rips. I'm copying existing ISO files, mounted in VCD, to a network drive.

[Woodstock]

Have you tried simply opening the ISO in MakeMKV, under Open->Files?

[koberulz]

It still crashed.

[Woodstock]

Searching Google for the error you're getting about the transport connection comes up with lots of hits for network issues, going back over 8 years, from a variety of programs.

One of several (not always successful) work arounds is to map the location as a drive; when a resource is MOUNTED, Windows does a few "extra" things to keep it mounted.