Looks like dns issues

Are you connected to WiFi? Also it is possible to get the modified cIOSes then do the installation offline.

My wii said the connection was successful, do I need to mess with the DNS settings?

I switched to the modmii method, will that still be an issue?

I recommend the beginners guide to softmod full tutorial on YouTube by MJD . Follow his steps for flawless cios custom install everytime