It looks like there are two localizations for German (almost certainly accidentally)
when attempting to checkout on a case aware but insensitive filesystem (oh the wonders of HFS+) there is the following gem of an error:
svn: In directory 'src/net/rptools/maptool/language'
svn: Can't copy 'src/net/rptools/maptool/language/.svn/tmp/text-base/i18n_de.properties.svn-base' to 'src/net/rptools/maptool/language/.svn/tmp/i18n_de.properties.tmp.tmp': No such file or directory
They appear to be the same file at the moment, so if one could be considered the correct name and the other removed I would be able to complete my checkout and hopefully submit some patches.