Probs installing the leaf theme

Hi,

Hope you can help me... :)

I installed Drupal 5.1. I Created a dir call themes in ..\drupal\sites\all and copied the contents of the leaf tar to ..\drupal\sites\all\themes\
I read on the leaf theme page that PHPTemplate needs to be installed. Since I'm running 5.1 it's not needed (I guess).

When I go to Administer / Themes the theme won't show! Any ideas?

Thanks a lot!