http://bugs.winehq.org/show_bug.cgi?id=23013
--- Comment #2 from Vitaliy Margolen vitaliy@kievinfo.com 2010-06-02 20:50:41 --- wine .wine/drive_c/Program\ Files/Nuance/NaturallySpeaking10/Program/natspeak.exe
You have to change current directory into program's directory (cd ~/.wine/drive_c/Program\ Files/Nuance/NaturallySpeaking10/Program).