PhabricatorRepositorySvnCommitChangeParserWorker can't process commits which delete a file from a relocate directory (if the directory also didn't exist in the previous commit). The problem is that the relocated directory path doesn't get added to the $add_paths variable so phabricator tries to look up the deleted from in the same location from the previous commit rather than in the location from which it was moved from.
To get an example of this is quite tricky so I've set up a demo svn repo here: https://subversion.assembla.com/svn/phabricator-example/
The basic steps to create your own are:
svn co $some_repo
mkdir ./trunk/foo
svn add ./trunk/foo
svn commit -m "Created directory."
svn rm ./trunk/foo
svn commit -m "Deleted directory."
mkdir ./trunk/foo
mkdir ./trunk/foo/bar
touch ./trunk/foo/bar/bad-file.txt
svn add ./trunk/foo
svn commit -m "Recreated directory."
svn rm ./trunk/foo/bar/bad-file.txt
svn commit -m "Deleted bad file."
mkdir ./branches/new-branch
svn add ./branches/new-branch
svn commit -m "Created a new branch."
cd ./branches/new-branch
svn merge -c 2 $some_repo/trunk
svn commit -m "Merge commit 2."
svn merge -c 3,4,5 $some_repo/trunk
svn commit -m "Bad commit: merge commits 3, 4 and 5."