In the video below, you will see the steps on how to correctly sync Social Prospector with an additional internal profile that you have created under your main account, provided it's different from your main profile.
Here is a recap of the steps you need to take:
Click on the Facebook icon located at the top right of the Social Prospector application.
Once you have opened the internal browser to your main Facebook account, click the profile image to switch profiles.
After successfully switching profiles, exit the internal browser and click the "Login Facebook" button.
You will then see that Social Prospector is connected to the correct profile and it will begin uploading the friend list for that profile.