Using subversion 1.5 I have branch B which was branched off of branch A. After doing work in both branches I go to merge changes from A into B (using svn merge http://
It means that there was a change in a file in branch A which Subversion tried to merge into branch B, but the file does not exist in branch B, so it has nowhere to merge the change. For example:
Now the change in README cannot be applied in branch B, because the file has been removed there.
EDIT: This will result in a tree conflict in Subversion 1.6.