Thank you for your advice however it seems that it is not solves the problem. Actually, after I tried
c = c_char_p(iconName.decode('utf-8', 'ignore').encode('ascii', 'ignore'))
The funny thing is that I can not go in the previous situation since the change
c = c_char_p(iconName.encode('ascii', 'ignore'))
is not make any improvement. I also tried with
c = c_char_p(iconName.encode("ascii", "ignore"))
but in vein.
I guess, tommorow I will upgrade in LM Mate 16 (now I am running 15).