svn 1.7 error E200009 Could not add all targets because some targets are already versioned

Seems like the correct behaviour for SVN 1.7. An alternative is to add only unversioned files:

svn st *.xml | grep ? | tr -s ' ' | cut -d ' ' -f 2 | xargs svn add

However it's possible you have nothing to add, so you will get

svn: E205001: Try 'svn help' for more info
svn: E205001: Not enough arguments provided

Related question: Add all unversioned files to Subversion using one Linux command

svn add something --force will solve the error E200009. In your case, svn add *.xml --force will solve your problem