报错，无法使用emerge

purepig@Gentoo ~ $ sudo emerge -av emacs
密码：
Traceback (most recent call last):
File "/usr/lib/python-exec/python2.7/emerge", line 50, in <module>
retval = emerge_main()
File "/usr/lib64/python2.7/site-packages/_emerge/main.py", line 1070, in emerge_main
return run_action(emerge_config)
File "/usr/lib64/python2.7/site-packages/_emerge/actions.py", line 4082, in run_action
emerge_config.args, spinner)
File "/usr/lib64/python2.7/site-packages/_emerge/actions.py", line 99, in action_build
old_tree_timestamp_warn(settings['PORTDIR'], settings)
File "/usr/lib64/python2.7/site-packages/_emerge/sync/old_tree_timestamp.py", line 98, in old_tree_timestamp_warn
time.strftime('%c', time.localtime(lastsync)))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe5 in position 4: ordinal not in range(128)