Hornet, there are characters in one of your ASCII files which are outside the ASCII range for characters.
The two places this error will show up are with the "information" text you enter or the skin name.
If you did a copy and paste to the information input dialog, it is probably there. Simply do the copy and paste it into "notepad", and save it, then copy that into the text input dialog. That should get rid of any non-ASCII characters.