Elisa, the firmware you modified with the ipod theme needs to be repaired then you should be able to load it.
I have added the menus from the Vista Theme but I can not test it because I do not have a player that suits your firmware. If your menus have text titles you may have to delete the text from the firmware by loading it into s1res and finding the text in UI30.RES>mstring and delete it.
You can download it
HERE .