I have files named XXX.part01.rar , .part02.rar , etc...
so it is commonly for winrar 3

But when i start unraring, winrar said that authenticity verification failed with each file.
All CRC are good (verified with .sfv and .par)

What should I do ?

Try uninstalling winrar 3.0 and then go to http://www.win-rar.com/index.php?lang=eng&bereich=download&PHPSESSID=2a7c21b65b58496b0f41578ee88726df
and grab winrar 3.2 and try that

I tried with winrar3.20 beta 2......still the same problem :(