can anyone help on how to get rid of anti pollution error on 307 hdi s 90?

i have read lots of peoples answers on here... i have just bought a 307 hdi 04 reg and after doin approx 10 miles the anti pollution error has come up, tok it back to the garage and they are goin to sort it at the weekend, but as i live 50 mile from the garage was wandering if any one had any ideas to save the journey...?