iTunes library file cannot be read

Hi there

I opened my iTunes library on another mac with iTunes 11. When I open my iTunes library with iTunes 10 on the mac where I had it in the first place it says: "The file 'iTunes Library.itl' cannot be read because it was created by a newer version if iTunes. Would you like to download iTunes now?" The only problem is that I haven't got Mac OSX 10.6 yet so i can't install iTunes 11. How can I make it work again without buying the new OSX. Please help

Regards Fabian