Try the new version of uLoader, uLoader 3.5, you will need a USB DVD drive, and will read only backups. To quote the readme:

Support for DVD USB Devices: It can run only DVD backups from .iso (original don't work because DVD drivers donīt support the Wii format). Remember you must insert a DVD to work at start the program. See "Mode DVD USB" below in this readme for more details
look here,