I want display the album hitcounter in the index page for each album,

I put below code in index.php of default themes,

but it displays an error:
Fatal error: Call to a member function getAlbumID() on a non-object

why?

Because you used a function as an class object function that it not is. Just getAlbumID()is enough.

thanks,I will try it tomorrow.

Just to add: The hitcounter does only work on index.php within the next_album loop that way.