SVN Server stopped working properly (403 Forbidden)

Ok, first of all, I've already googled a lot about this problem, but didn't found any solution... I've searched here and on ServerFault, but didn't found anything, so I end up posting this question here (don't really sure if it goes here or in ServerFault, sorry).

So here's the deal: We have a Windows 2003 Server running without problems. We have been using Visual SVN Server as our Subversion server and it worked great until now. We take some vacations for a couple of weeks so we didn't use the SVN at all. Today, when I tried to commit something I got:

Server sent unexpected return value (403 Forbidden) in response to OPTIONS request for [repository url]

We use TortoiseSVN as our svn client, but the problem seems to be on the server. We tried creating a new repository and import new files, same error. We tried accessing the SVN server from the server itself through RDC and trying to checkout something by console (svn checkout) and others commands too.... everything leads to that error.

Some people said it was a case-sensitive problem on the URL... but that's not our case... I've double-checked the URLs and they are fine... (anyway they were stored on the Tortoise history, so that didn't change).

One particular point to say is that there are people out there having the same problem that are not using Visual SVN (which is really just a easy way to set up a Subversion server in 2 clicks, it's not something different from any Subversion server). So I don't know if the problem is actually the Visual SVN itself.

We're lost... Any helpful information will be really appreciated.

EDIT/SOLUTION: I had a wrong entry on the authz file. It was trying to give permission to a deleted group (I think VisualSVN didn't delete the entry on authz but it did delete the group), so I deleted the entry and it's working now.

Thank you

I have a wrong entry on the authz file (it was trying to give permission to a deleted group), so I deleted the entry and it's working now