I accidentally deleted a folder in SVN and added it back immediately. I ran into an issue with this and my solution ended up removing the folder completely from my local copy as
This means that the folder/file that you are trying to put on svn already exists there. My advice is that before doing anything just right click on the folder/file and click on repo-browser. By doing this you will be able to see all the files/sub-folders etc that are already present on svn. If the required file/folder is not present on the svn then you just delete(after taking backup) the file that you you want to add and then run an update.