You can check if a PO file is valid with the following command:

        msgfmt -c -o /dev/null <po file>
      

The following errors were found in scratch 's PO files:

gettext: locale/da.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/es.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/et.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/eu.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/fa.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/fi.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/he.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/is.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/it.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/ja_HIRA.po: can't guess language
gettext: locale/ko.po: warning: Charset missing in header.
                                                                      Message conversion to user's charset will not work.
gettext: locale/lt.po:452: keyword "Scratch" unknown
locale/lt.po:452:22: syntax error
locale/lt.po:1499: keyword "a" unknown
locale/lt.po:1499:17: syntax error
locale/lt.po:1946:18: syntax error
locale/lt.po:1946: keyword "o" unknown
msgfmt: found 6 fatal errors
gettext: locale/mr.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/nl.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/pt_BR.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/sk.po: warning: Charset "CHARSET" is not a portable encoding name.
                                                                      Message conversion to user's charset might not work.
gettext: locale/sl.po: warning: Charset missing in header.
                                                                      Message conversion to user's charset will not work.
gettext: locale/sv.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/tr.po:1:2: syntax error
msgfmt: found 1 fatal error
gettext: locale/vi.po:1:2: syntax error
msgfmt: found 1 fatal error
      

Please ask the translator (identified by the Last-Translator field in the PO file), the language team (identified by the Language-Team field) or debian-i18n for a fix.