This client is too old to work with working copy '/Users/
The tool /usr/local/bin/change-svn-wc-format.py
may be used to convert this working copy to match this SCPlugin (see 'About'), but you will loose any features of the newer Subversion you may be using
I tried googling but unfortunately I couldn't find any solution and after some couple of weeks I found some how to do uninstall it.
Please remove /Library/Contextual Menu Items/SCFinderPlugin.plugin
Remove /Library/Receipts/SCPlugin.pkg -> version might be also appended sometimes
Remove /Library/Receipts/Subversion.pkg.
Feel free to ping for any help.