[Mark McLeod]

You will need to use the White Arrow only from the Robot Main.vi, rather than from the individual vi's such as Teleop.

Robot Main calls everything else, so Begin gets called to open devices and Teleop gets called when the Driver Station is put into Enabled/Teleop mode.
Trying to use the White Arrow in Teleop, first doesn't have any devices open, and second will only execute a single time, since Teleop is normally called from a loop in Robot Main.
You can open any of the vi windows while the program is running in debug and see what's getting updated in each block diagram and on each front panel.