Odd svn.collab.net behavior

My up to date client bits from trunk issue this HTTP request to
svn.collab.net to try and merge the latest trunk bits into the 1003
branch.
 
Here's the outgoing request (more or less)
 
REPORT /repos/svn/trunk HTTP/1.1
Host: 216.127.237.133
User-Agent: neon/0.23.5 SVN/0.16.0 (dev build)
Connection: TE
TE: trailers
Content-Type: text/xml
 
<S:update-report xmlns:S="svn:">
<S:target-revision>4186</S:target-revision><S:dst-path></S:dst-path><S:e
ntry rev="4186"></S:entry>
</S:update-report>

svn.collab.net returns my polite request for an update report by closing
down the TCP connection without so much as a HTTP failure response code.
 
Is the installed mod_dav_svn too old, or is this some other issue?
 
Thanks,
Bill

----
Do you want a dangerous fugitive staying in your flat?
No.
Well, don't upset him and he'll be a nice fugitive staying in your flat.