There are two cases where I've seen this. First, press CTRL+F5 to refresh Windows Explorer. Sometimes it just gets out of sync, especially after you've just done a commit. Second, right-click the folder and select TortoiseSVN > Check for modifications. This will bring up a dialog showing all the files that TortoiseSVN thinks have changed and you'll either see a file you missed and/or one that is marked hidden (and you haven't set Explorer to display hidden files).
You are missing the folder/file representing the activity db. This can happen if you use robocopy (or similar) to copy the Repository directory and you have it ignore empty folders. Also, this normally only happens with new repositories, so re-creating it should fix it.
If you're just trying to find out how to do something with Subversion or TortoiseSVN, I recommend first checking TortoiseSVN's help file which comes with the install. It has lots of pretty pictures.
Windows Explorer isn't always the most trust-worthy program and its views get out of date quite easily. TortoiseSVN suffers the same fate, because it is an extension. If you don't see icon overlays change, make sure to hit refresh. If options don't appear that should (such as TortoiseSVN > Add inside a working copy), you might need to kill and re-launch explorer.exe or log out and then back in.
Case Sensitivity: both for usernames and files/folders; it is possible to have two files with the same name, but different case (a vestige of its *nix roots). This screws up TortoiseSVN beyond belief.
mod_auth_ldap.so; was working; now getting 401 UnauthorizedI wish I knew why this starts happening. The only way I've found to fix it is to reboot the box, restarting Apache doesn't appear to help. My only theory is that someone keeps trying to access something with incorrect credentials and eventually the LDAP stuff just stops doing actual lookups and starts failing immediately.