Files installing corrupted

I recently modded my Wii so I could play some older games that I've been having issues finding and I haven't had an issue until I tried downloading files bigger then 700 MB. Games such as City Folk, Wii Sports, etc which are all under 600-700 MB download just fine but anything bigger then that ends up installing as a corrupted nkit file that can't be unzipped. I've tried multiple programs to unzip it including WinRAR and 7z, I've tried converting the nkit file into IOS, I have tried using my phone to install it, I've tried downloading wbfs files and nkit files, I've tried at least 5 websites and I've tried multiple browsers but no matter what I try I can't get the files to download correctly. Does anyone have an idea what the issue may be or has had the same problem? My PC installs DSI & 3DS games just fine with no issue, regardless of their sizes.