Can someone give me some advice about the judgement on my credit report?

I never had a credit card but wanted one . I applied at small department stores to get my first credit card but i was denied for insufficient credit . Being offered a free credit report i wanted to see what was on it. Everything was clear but it said i had a judgement of 8,000 dollars plantiff was the probation office I was entitled to pay restitution and signed a plan to pay 250 everythin month for 3 years but i paid everything off in just 6 months . How can they put a judgement on me when id id make my payment on time...i signed a form indicating i will pay every month..aren't judgements given to those who don't pay their debt or restitution. Do i have the right to dispute this ..Is this information on my credit inaccurate . I'm really concern now > I wanted to get my first credit card and start building credit to have a sucessfull future . I went from No credit To judgements on my credit .without ever having a credit card on my hand. please HELP.