Don't use pimpmywii. Do you have the homebrew channel to begin with? If you're wanting to softmod your wii just use modmii:
http://gbatemp.net/threads/modmii-for-windows-official-support-topic.207126/ You'll notice there's a huge stickied support thread here for ModMii and not for pimpmywii. When you softmod a Wii you need the following things:
-Official IOS58 which is bundled with system menu 4.3 but can be downloaded seperately (optional but highly recommended for USB 2.0 support)
-Homebrew Channel
-Homebrew Applications/Emulators (optional)
-cIOSes (required for backup loaders)
-Backup Loader (optional)
ModMii is a PC application provides you with all of these. It will even update an outdated softmod. PimpMyWii is a homebrew Wii application (so requires the homebrew channel to begin with) that will install cIOSes for you, but it will patch every IOS you have installed in one swoop. That's not good. Your wii has many different copies of its operating system that are used in different situations. They are known as IOS. Custom IOSes are heavily patched and used to run backup/pirated Wii Games. They're installed in their own slots that nintendo software doesn't use. PimpMyWii applies at least some patches to everything. Doing this is asking for trouble. If something goes wrong and the IOS that runs your System Menu gets corrupted then your Wii is Bricked. That risk doesn't exist with ModMii and just installing cIOSes. There's no reason to patch the IOSes that are used by Nintendo software.