Time machine problems

Today I noticed my black macbook (2008) had a failing hard drive, i went to apple and they told me to back up my hard drive and bring it back. So i bought a hard drive from apple (http://store.apple.com/us/product/TV523VC/A?fnode=MTY1NDA0Nw&mco=MzkxMTkxMQ) and hooked it up, set it up as my backup disk and all of that.
Everytime I try and get it to work i get "Unable to complete backup. An error occurred while copying files to the backup volume."
I look in console for errors and i see like a million

a lot of others

And finally the

what can i do?