Having trouble connecting Replicator to Sprinter

I'm new to this game-have Sanguinololu v1.2 board that come loaded with Sprinter. I have the board working with the test program that I loaded using Arguino-when i put the Sprinter firmware back in i have no response from ReplicatorG- it won't connect. Is there anyone else who has this combination who can help me sort out/missed something in the loading ?????

I am not very familar with your board but I was having simular issues using RAMPS/Arduino & Sprinter set up. The main issue was that the firmware needed to be configured to my specific set up. Using the arduino sketch program I went into the configuration file, altered it to select my electronics set up (this case RAMPS 1.4), my thermister values (100k and 10k), and pin layout.