How to update an SVN branch made with svn-copy?

That error message occurs when someone deletes something without telling Subversion about it. If you were to run svn status on that working copy the same path that Subversion is complaining about should show with a ! in the first column of the output. Usually this means that someone used an OS command to delete paths rather than a svn command.

If you really want the paths to be deleted then you can fix this by telling Subversion about this by doing using the svn rm command. The paths will show as deleted with a D in the first column of status output and your merge should proceed (though you might have tree conflicts).

If you want the gory details see issue #2915 from the Subversion project that explains why this error message was added.

If you are working in windows and the path exceeds 256 characters, Windows will start being nasty about things. I usually get around this by creating the workspace directly under a short directory in root file system (e.g. C:\WRK) This will use a path much shorter than C:\Users\user_name\Desktop\ directory. Once I have my workspace created, I add a shortcut to my desktop for easy access.