There is a pair of duplicate keys in i18n.properties file :
SignatureTest.error.sigfile.missing=Signature file name not specified
SignatureTest.error.sigfile.missing =Can't find reader for {0} or file doesn't exist
SignatureTest.error.sigfile.missing=Signature file name not specified
SignatureTest.error.sigfile.missing =Can't find reader for {0} or file doesn't exist