Quinctia, I had a hard time getting sim surgery to work for me for the longest time until i did a little cleaning and organizing my download folder...
I put all my Body/Clothing meshes in one separate folder and my skintones in another separate folder and then add those 2 folders to SimPe's file table in preferences... If sim surgery barfs up an error when you try to copy a skintone then it can't find the Body Mesh most likely.... good luck