The chances are not good in view of summer season rush. Plus you have ticket Dadar-Ratnagiri whereas end to end station tickets get better/more chances in confirmations. Goa being a hot tourist stop, heavy bookings on this train.
Need may arise to try out in Tatkal booking which will open on 16.5.2010. It (WL Nos.) had suddently moved in the past in view of summer special trains announcements/bookings.
Post your PNR No. plz.