If your copy of Data Synchronisation Studio fails to open the main window when you run the program it could be that the window location file is corrupt.
The easiest thing to do is to remove your local settings for Data Sync and let it start from a clean start. Delete the following directory replacing 'Sean' for your profile name.
Now when Data Sync starts it will start with default settings.
Note: This directory maybe hidden on your system so you might need to show hidden files.