You extracted the entire folder (the folder itself included) into the apps folder on the SD card, correct?
Then loaded the HbC, and selected the usbloader_gx?
If so, it should work. If not, try the latest build, or waninkoko's or cover flow loader.
By the way, starting at step three, did you install DVDX and bootmii? bootmii is apparently as a safeguard, and DVDX to read regular DVD media.