I'm not sure he was on unsupervised probation. His original statement says he quit going to his PO (sounds pretty supervised to me).
Not being able to pay is one thing, absconding is another. You can probably rest assured that the thing didn't just go away.
As a PO, I gotta agree with Ron. We can work out payment plans with probationers if they are willing to put forth effort. If they take off, we ask the Court to issue warrants for their arrest. The OP needs to hunt up the money to pay off the fines, and to hire a lawyer to represent him on the Petition to Revoke Probation that was filed in 2007.
Oh, and the probation period has not expired. Once he took off and that PTR was filed, the probation period was tolled, or stopped running. He still owes 9 months of probation. The PO will probably recommend the jail sentence be executed, and that the person go to jail to serve the sentence. I would if he were on my client list.