There is a couple of versions of xDelta floating around. I'm not sure exactly where OP was intending for us to find a download. The one I found, threw the same errors that you are describing at first.
Pay VERY close attention to the naming of the exe that you download. I believe I had to rename that exe to match 'xdelta-3.1.0-x86_64.exe' which is what the batch file is looking for. If the name is different, the batch file fails to patch but still moves the unchanged cache files to the 'patched' location (this is why it mentions that the files have been moved).
That said, even with the correct name change, the first 3 files work, but dlc4.vpp_pc (the largest) still failed to patch for some reason so I ended up crawling my way through the manual edit instructions using HxD hex editor directly on the cache file. It's not horribly difficult but it is extra fuss. I eventually just got comfortable doing the manual hexedit method on all 4 vpp's and skipped the xDelta method entirely. I hate having more than one download tool to fix a single issue.