the theme download feature is broken because the website hosting the themes blocked the direct linking.
Now, downloading theme require registration and advertisement.
As it can't be done from the loader anymore, I added a message to explain that themes can't be downloaded anymore from spiffy.com using the loader.
But you can register and download them with your computer, then extract them to the themes folder on your SD card.
sorry, I didn't read your issue carefully.
But usually it's very easy to softmod, using automation tools are not a good idea to me.
I prefer being aware of what I do to my console instead than letting a random program do unknown things.
What you need is very simple :
1. install HBC
2. use d2x cIOS installer to install 2 custom IOS (d2x base 56 in slot 249, and if you want to play call of duty you also need to install d2x base 57 in slot 250)
3. ... there's no 3 ! Done !
then download and extract the usbloaderGX revision from my signature to your SD card and launch from HBC.
once inside the loader, insert your Wii or Gamecube discs to copy/install the games to USB or SD card (wii games only no USB, gamecube and Channels SD or USB).
if it still blackscreen, it's probably an issue with video mode.
be sure the settings are set to use "disc default" (or game default)