Ah, there's your problem! Windows does not support symbolic links, so 7z just extracted it as a file.
EDIT: I guess it does support a sort of symlink, but not the kind that's compatible with Unix-like systems. So it could not work when you copied it over anyway.
EDIT: I guess it does support a sort of symlink, but not the kind that's compatible with Unix-like systems. So it could not work when you copied it over anyway.