If it hangs on this message it's probably fine.
* Wait 30 seconds to make sure it's finished.
* Hold the Wii power button for 5 seconds to turn off you Wii
* Hold down reset
* Turn on Wii (keep holding reset)
* Preloader should start
* Go to settings
* Change the IOS to 30 or 60 (IOS30 for Wii System 3.2x, and IOS60 for Wii System 4.0x)
* Restart, all should be fixed
I believe this happens when you had 3.2, installed preloader, upgraded to 4.0, installed preloader again. Preloader remembers that it used to use IOS30 and tries to use that, but it needs IOS60 to boot v4.0-
source - Talk:Preloader - WiiBrew
Did you install the patched IOS60?