Go to this page:
http://team358.org/files/programming...2009-/LabVIEW/
Find the example that says "Single Solenoid Example". Replicate the code in the Begin.Vi section of the image in your Begin.VI. The Solenoid open will have a box under it that says "Single" that is not pictured. You should have one copy of this little code snippet for each line sensor with the appropriate channel and a different refnum name for each one.
In your autonomous VI replicate the green Solenoid VIs from the section of the image which says Teleop.VI (you don't need the joystick part). You will need one copy for each sensor with the names matching the ones you used in Begin. Instead of wiring in a button, right click on the terminal, and go to Create->Constant. Then set the constant to True.