With ImgBurn in Read mode, insert the original bootable DVD and then look which filesystem(s) it has. If I recall correctly Windows shows CDFS for all ISO9660, Joliet and UDF filesystems
You can get DVDInfoPro at http://www.dvdinfopro.com/
Looks like your drive misreported the disc's size (maybe a bug in the firmware?). The disc should work fine from what we can see
Use ImgBurn's Verify mode to check that disc against that same image.
As for the Wii needing a modchip or something we don't really know. Have you searched with Google? I think you'll find there all the answers you need
A log from that burn would be more helpful. Copy from the Log window (which you shouldn't have closed ) or, if you closed ImgBurn after that, look in the Help menu.
When it gets stuck, can you cancel the burn in ImgBurn? Does the computer work OK when the burn is stuck? Also please post your Filter Driver Load Order (look in the Tools menu).