First I would like to suggest you use USBLoader GX r1209 (copy the boot.dol over the v3 boot.dol, "Sd:\Apps\usbloader_gx\boot.dol").
Next I also suggest you use DMToolbox (included with DiosMios 2.6) to manage/convert your gamecube games. For the GameCube games I believe they have to be in a...