Uninstall the entire G2 program and disconnect the USB Tx. Restart your computer.Then install the program again , after that install the USB controller. Restart again. Choose calibrate controller automatically.Leave switch assignments as they are, throttle hold will be automatically assigned to the right switch on top of the transmitter (is it Mode 2?). Have you droped the Tx or something? Upgrade the G2 program on-line using the Realflight control panel. Before uninstalling note down the product id and registration numbers.
Also, open the on screen view of the virtual radio and see how the lettering on the virtual transmitter turn red on and off when turning switches on and off. What you are refering to as "throttle cut" is actually "throttle hold"