Redmine

Where do you see these messages ?

AFAIK, this: /svn-browse/documentation/!svn/bc/145 is not a Redmine url.
The exclamation mark in the url makes me think about this rails plugin: https://www.bountysource.com/
Do you use this plugin ?

Well as I said they are the output of the command I specified. I don't have any plugin installed. No idea about the url.

Can only guess, but if the script is working properly with other names it could crash to the "documentation" name. Then again, you can try other name for the project or post the script that is doing the fetching.

I get the following weird error message (200 OK shouldn't be an error?)

This a svn error message, not a Redmine's one.
What's your repository url ? And what do you get when you manually run the following ?

svn info <url>

I met that error when I try to access a svn served via HTTP with a proxy that don't understand WebDAV extensions. Have you other http svn repository outside your network?

The URL is http://localhost/svn-browse/documentation/ and if I try svn info I get the following:

naderman@phpbbsvn:/svn/documentation$ svn info http://localhost/svn-browse/documentation/
Path: documentation
URL: http://localhost/svn-browse/documentation
Repository Root: http://localhost/svn-browse/documentation
Repository UUID: e96c91bf-73f8-46e7-b89f-1e31f7b18a0a
Revision: 145
Node Kind: directory
Last Changed Author: naderman
Last Changed Rev: 145
Last Changed Date: 2008-03-07 16:06:07 +0100 (Fri, 07 Mar 2008)

Not sure what you mean with outside my network? There are thousands of svn repositories online (outside my network) ;-)

Redmine and svn are on the same host ?

To see what is going wrong with your repository, you can set Redmine log level to debug (uncomment config.log_level = :debug in config/environment.rb then restart) to see the exact svn commands that are ran against your repository. You will see lines like this in the log file:

Shelling out: <svn command>

Try to run these commands manually to find which one gets the "svn: REPORT request failed" error.
Again, this error is not reported by Redmine but by svn.

Alright apparently the weird message is caused by http://subversion.tigris.org/issues/show_bug.cgi?id=3102 so I don't get to see the actual error message.