I got this recently when suping:

[...]
SUP Receiving file pkgsrc/lang/perl5/pkg/PLIST-md.shared
SUP Receiving file pkgsrc/lang/perl5/pkg/PLIST-md.static
SUP Receiving file pkgsrc/lang/perl5/pkg/PLIST-mi
SUP: SCM GOAWAY We died trying to gzip pkgsrc/lang/python/Makefile
SUP: Premature EOF on network input
SUP: Error receiving file from file server
SUP: Upgrade of current-pkgsrc aborted at Feb  1 16:45:32 1998
SUP: Aborted

   And here is the relevant config file entry:

current release=pkgsrc host=sup.netbsd.org hostbase=/ftp/pub base=/usr prefix=/usr backup use-rel-suffix delete compress

   And the command I used was "sup -v /etc/sup.conf". Naturally,
I tried using the "-Z" option to turn off compression, but it seems
that that flag does not perform as advertised, since it still tried
to do compression and gave the same error.
   The next step was to try removing the compress option. I tried
commenting it out using '#' since it was the last option, but it
seems that '#' only works as a comment as the first character on
a line. Unless there is some reason to want the pound sign in the
middle of a config line, it would be nice if it would comment out
the rest of a line. A minor nit, of course.
   Once I had compression unconfigured, it gave me this:

[ ... ]
SUP Updating file pkgsrc/lang/perl5/pkg/PLIST-md.static
SUP Updating file pkgsrc/lang/perl5/pkg/PLIST-mi
SUP: File server unable to transfer file pkgsrc/lang/python/Makefile
SUP: File server unable to transfer file pkgsrc/lang/python/files/Setup
SUP Created directory pkgsrc/lang/python for pkgsrc/lang/python/files/md5
SUP Created directory pkgsrc/lang/python/files for pkgsrc/lang/python/files/md5
SUP Receiving file pkgsrc/lang/python/files/md5
SUP Created directory pkgsrc/lang/python/patches for pkgsrc/lang/python/patches/patch-aa
SUP Receiving file pkgsrc/lang/python/patches/patch-aa
SUP Receiving file pkgsrc/lang/python/patches/patch-ab
SUP: File server unable to transfer file pkgsrc/lang/python/pkg/COMMENT
SUP: File server unable to transfer file pkgsrc/lang/python/pkg/DESCR
SUP Created directory pkgsrc/lang/python/pkg for pkgsrc/lang/python/pkg/PLIST-md.shared
SUP Receiving file pkgsrc/lang/python/pkg/PLIST-md.shared
SUP: File server unable to transfer file pkgsrc/lang/python/pkg/PLIST-md.static
SUP Receiving file pkgsrc/lang/python/pkg/PLIST-mi
[ ... ]

   FYI.

                                      Gary D. Duzan
                         Humble Practitioner of the Computing Arts