do you consider _s to be special characters?
It's not me... it's the compiler output that my code parses. I honestly don't know exactly what the compiler considers special. All I do know is it worked when I tested on all 3 platforms. But I rarely use Windows, so I probably just put it in c:\arduino for testing. Likewise, on Mac and Linux I'm sure I never tested with spaces in the directory name.
Did I mention the part about not having the time to investigate this..... and hoping someone might go to that trouble and submit a high quality bug report, detailing what does and does not work on various platforms?
If you turn on verbose info, from File > Preferences, when the patch is working you should see messages about using already compiled files. Try compiling an example for Arduino Uno on 1.0.3 to see it work. Or watch this video I made... before it was accepted into Arduino, when the Arduino Team wanted to see more people test it first.
The point is not that I can help you. I've already done everything I can for now. The point is this patch exists and some Windows users find it works, others don't. You might be able to get it working somehow. So far, absolutely nobody on Windows has ever submitted any good info about what does and does not work (this isn't the first time I've asked....)