I recently installed on my Windows XP box the Collabnet Subversion 1.6.5, including the Apache 2.2 distro that comes together with it.
When I tried to start the http server, I would get an error message:

>>> httpd.exe: Syntax error on line 116 of C:/Program Files/CollabNet Subversion Server/httpd/conf/httpd.conf: Cannot load C:/Program Files/CollabNet Subversion Server/httpd/modules​/mod_dav_svn.so into server: The specified module could not be found.

After quite a while of googling and experimenting I found out that there are 2 (or ate least one) things one should do to make it work.

1 - Make sure that collabnet subversion folder is at front of the path. If this is not the case, move it to front and restart the system.

This one worked for me already, and Apache would start perfectly, but then I went on just to be sure:

2 - Click "properties" in Apache service and change logon option from "Local system account" to "This Account" and start the service.

Cheers