mpitune get "could not dump the session, because unknown encoding: utf-8"

Hi forum,

I try the following command on a server: (impi 5.0.2.044, icc 2015.2.164)

mpitune -of analysis.conf -application \"mpirun -n 24 -host `hostname` ./myexe\"

It did run for a while but output nothing of analysis.conf. Meanwhile the console output message like:

ERR | Could not dump the session, because unknown encoding: utf-8

I try to change LANG=C, as locale outputs:

LANG=C

LC_CTYPE="C"

...(all other environment variables are "C")

How can I run successfully of mpitune to get analysis.conf which has real contents. Thanks!