It looks like you TabPy server isn't finding scikit-learn. Are you able to import other modules from scikit?
One thing to do is make sure sklearn is installed in the environment where you have TabPy installed. You should be able to access the environment from the command line using: <activate my_tabpy_environment> where my_tabpy_environment is the name of the python environment you created to hold tabpy. Then simply run <pip install sklearn>