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 cadaver 's PO files:

gettext: po/it.po:719:40: invalid control sequence
po/it.po:719:64: invalid control sequence
po/it.po:740:27: invalid control sequence
po/it.po:864:23: invalid control sequence
po/it.po:864:51: invalid control sequence
po/it.po:957: duplicate message definition...
po/it.po:944: ...this is the location of the first definition
po/it.po:1061:17: invalid control sequence
po/it.po:1073:32: invalid control sequence
po/it.po:1129:26: invalid control sequence
po/it.po:1134:44: invalid control sequence
po/it.po:1144:37: invalid control sequence
po/it.po:1149:37: invalid control sequence
po/it.po:1153:33: invalid control sequence
po/it.po:1158:33: invalid control sequence
po/it.po:1171:3: invalid control sequence
po/it.po:1172:25: invalid control sequence
po/it.po:1187:7: invalid control sequence
po/it.po:1188:24: invalid control sequence
po/it.po:1219:18: invalid control sequence
po/it.po:1291:44: invalid control sequence
msgfmt: too many errors, aborting
      

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.