Money Owed to an Apartment

I was living with a roommate in 2008 (in Scottsdale, AZ) in an apartment which had both of our names on the lease. I moved out and regrettably did not have my name taken off the lease. The other roommate moved out 2 months later without paying the rent.

Now, anytime I try to get an apartment no one will lease to me because the money owed to the old apartments shows on my credit since my name was never taken off the previous lease. I have been renting privately since then but would like to be able to get a place with my name. There is about $2,000 owed which I feel I shouldn't have to pay because I wasn't living there.

How do I fix this on my credit history?