svnsync sync error parsing arguments

As near as I can tell, I successfully initialized the mirror. That is,
it gave me no error messages the first time I ran the initialization.
(I didn't record all this, sorry.)

When I tried to sync, it gave me this:

-----------------
$svnsync sync https://svn.sourceforge.jp/svnroot/bif-c/
https://svn.code.sf.net/p/bif-c/code --sync-username reiisi
--source-username reiisi
svnsync: $B$h$j>\$7$/CN$j$?$$$H$-$O(B 'svnsync help' $B$r;n$7$F$_$F$/$@$5$$(B
[For details about svnsync, try svnsync help.]
svnsync: $B0z?t$r%Q!<%9$9$k:]$K%(%i!<$,@8$8$^$7$?(B
[Error parsing arguments. (If the error message was correctly
translated into Japanese.)]
----------------

svin info gives me this much:

------------------
$svnsync info "https://svn.sourceforge.jp/svnroot/bif-c/" --sync-username reiisi
$BG'>ZNN0h(B: <https://svn.sourceforge.jp:443> SourceForge.jp Subversion
'reiisi' $B$N%Q%9%o!<%I(B:
Source URL: https://svn.code.sf.net/p/bif-c/code
Source Repository UUID: 40e07b2b-f213-4bbf-ac1f-8f4869237126
Last Merged Revision: 0
$ svnsync info "https://svn.code.sf.net/p/bif-c/code" --source-username reiisi
Source URL: file:///nfs/classic/sf-svn/b/bi/bif-c
Source Repository UUID: 40e07b2b-f213-4bbf-ac1f-8f4869237126
Last Merged Revision: 15
------------------

I don't have access to set the hooks myself, but the admins at
sourceforge.jp say they set start-commit and re-revprop-change to
allow any member of the project on sourceforge.jp to sync. Which
should be sort-of okay, since the project is strictly intended as a
mirror, and the only members of the project will be mirror
maintainers.

Any suggestions?

-- 
Joel Rees
Be careful where you see conspiracy.
Look first in your own heart.