"invalid character" error on Ubuntu 11.04

A program reported invalid character error when process a file of EUC-JP encoding. Most common recommendations are adding ja_JP.EUC-JP in

/var/lib/locales/supported.d/local

sudo dpkg-reconfigure locales

and changing changing LANG and LANGUAGE to ja_JP.EUC-JP

/etc/default/locale

They don't fix the error. At last, my problem was solved by changing the LC_CTYPE in terminal before invoking make.

export LC_CTYPE=ja_JP.EUC-JP