The following is wrong:
When tuning param for moses using mert-moses.pl, you should create the two folder mert/ and extractor/ first. Otherwise, you will got error by line 303 or 304 in mert-moses.pl .
If you get errors like
Exit code: 127
Failed to do extraction of statistics. at XXX/scripts-YYYYMMMDD-XXXX/training/mert-moses.pl line 662.
set –mertdir = XXX/moses/mert/, which contains extractor etc.