Setting up a Subversion server on Windows

I found mostly excellent instructions on the TortoiseSVN site for setting up a Subversion server on Windows. Included: setting up Apache 2, setting up Subversion, setting up Windows domain authentication, setting up SSL. Quite a decent start. Unfortunately, I am now facing:

<?xml version="1.0" encoding="utf-8"?>
<D:error xmlns:D="DAV:" xmlns:m="http://apache.org/dav/xmlns" xmlns:C="svn:">
<C:error/>
<m:human-readable errcode="165005">
Expected version '2' of repository; found no version at all; is 'C:/SVN/local' a valid repository path?
</m:human-readable>
</D:error>

Time for some Google research.