I think I found out what was the problem. I'm almost sure it was my anti-virus software which marked my sh3.exe file as a threat and that's why the OptionsSelector couldn't locate it. After all, I shouldn't have to reinstall my whole Op system, all I really had to do was just disabling my anti-virus software for a couple of minutes and in that way could've done the patching without a single trouble.
But it doesn't matter, at least I learned something new this day, too.