Not sure if it'll help, but here's the exact method I used to install:
- Renamed existing Gmenu2x folder "Gmenu2xold"
- Copied new folder onto card, ensuring it was named Gmenu2x
- Left original files (autorun script etc) on root of card
- Copied shortcut & skin folder contents from Gmenu2xold to Gmenu2x. (I checked and copied the contents of each folder manually, ensuring that no new files were overwritten by old versions).
The new Gmenu then fired up and ran as normal on reboot.