IOS30 v2576 is the correct version for 3.3.
IOS249 v65280 is the stub that comes with 4.2
Not sure why anyone would need to install IOS21.
IOS30 v2816 is undoubtedly the stub IOS30 that Nintendo update all Wiis above 3.4 with.
So there you go, you stub bricked your Wii. Manually installing IOS for which you have no idea as to their operation is a bad idea, as you have discovered.
Hold reset when you start the Wii to check for Preloader.
Watch the DVD slot (when no disc inserted) when you power on the Wii for two quick flashes.