Long story short, the software does not work correctly, but there's a workaround.
You cannot upload the ARB file using the "ARB WaveForm Creator" software.
You have to:
1. Design your waveform
2. Click "Down current ARB" - This will save your waveform to a file
3. Open the sig-gen virtual control panel
4. Right-click on the virtual control panel and select "Send ARB File"
5. Select the file you created in step 2 (above) and click "LOAD"
The UTG962 will automatically switch to the ARB waveform you just uploaded.
A few things that I don't like:
1. Although rudimentary, the software could really have been better by allowing this simple "load" action from within the software itself.
2. It should allow me to save my waveform to internal memory, it currently goes lost on power-off. The portability of this device is extremely useful, but less so if I have to drag my laptop along to load my ARB waveform each time. This is an unfortunate oversight by UNI-T. Not sure how easy this would be for them to fix via a firmware update.