Confirm that the error does not exist when the module is not being called. (ie, Remove {$giftbox} from your template. Is the error gone?) If the error isn't gone, it's nothing to do with this. If it's gone, then make sure the name is correct. (Again, as stated in the tutorial, if you named it anything else, you'll be calling it with that name.)
Otherwise... eh, this was one of my first mods.