There is a known bug in the server for CVS 1.9.18
and older which can cause this. For me, this was
reproducible if I used the `-t' global option. It
was fixed by Andy Piper's 14 Nov 1997 change to
src/filesubr.c, if anyone is curious.
If you see the message,
you probably can just retry the operation which failed,
or if you have discovered information concerning its
cause, please let us know as described in H. Dealing with bugs in CVS or this manual.
Our cvs is version 1.11 and we don't normally use the -t option which is why it never came up. Running the exact same command outside of hudson was the clue. Thanks for the help!