I tried your svn diff directly, and got the same error:
$ /usr/bin/time -v -o /tmp/svn-log svn diff -r7604:8870 https://ironpython.svn.codeplex.com/svn > /dev/null svn: E000104: Error running context: Connection reset by peer
$ more /tmp/svn-log Command exited with non-zero status 1 Command being timed: "svn diff -r7604:8870 https://ironpython.svn.codeplex.com/svn" User time (seconds): 0.14 System time (seconds): 0.03 Percent of CPU this job got: 0% Elapsed (wall clock) time (h:mm:ss or m:ss): 7:32.71 ...
So the other end decided to drop it after 7 and half minutes. You said you were successful, so this seems connectivity/server-load related?
I suppose I could keep fetching to see if I can get past that rev one day :-(.