If so, it uses the L'OpenTour buses and you will need to visit their main office in Rue Auber to exchange your ticket for your bus pass.
You will need to take the #54 pink shuttle bus (free) from the Holiday Inn to the station just outside the Disney parks, then catch the RER to Auber station. These run very frequently and the journey will take about 40 minutes. When you come out of Auber station take the exit marked Sortie Rue Auber and the L'OpenTour office is just across the road and to the right.
On your return, DLRP is the last stop on Line A4 and the station is called Marne la Vallee-Chessy.