Svn client doesn’t work after upgrading to 1.7: working copy is too old

One approach would be to:

1. Copy edited items to another location.
2. Delete the folder containing the problem path.
3. Update the containing folder through Subversion.
4. Copy your files back or merge changes as needed.
5. Commit

Another option would be to delete the top level folder and check out again. Hopefully it doesn't come to that though.

If you look on the release notes for subversion 1.6 you will see the following

The working copy format has been upgraded. This means that 1.5 and older Subversion clients will not be able to work with working copies produced by Subversion 1.6. Working copies are upgraded automatically.

So if you use a 1.6 based client, no previous versions will work. On further reading of the release notes you should be able to downgrade your working copy if required...

WARNING: if a Subversion 1.6 client encounters a pre-1.6 working copy, it will automatically upgrade the working copy format as soon as it touches it, making it unreadable by older Subversion clients. If you are using several versions of Subversion on your machine, be careful about which version you use in which working copy, to avoid accidentally upgrading a working copy. (But note that this "auto upgrade" behavior does not occur with the repositories, only working copies.)

If you accidentally upgrade a 1.5 working copy to 1.6, and wish to downgrade back to 1.5, use the change-svn-wc-format.py script. See this FAQ entry for details, and run the script with the --help option for usage instructions.