That reactor looks very nice. I hope it works as well as it looks. It's a shame I didn't gave the space to do this also.
Milwaukee controllers are pretty reliable so I'd think the regulators would be also. When the solenoid is supposed to open can you hear 'click' as it opens? If so, did you open the needle valve to verify no bubbles come out and the solenoid isn't working?
The needle valves can be kind of finicky and sometimes need to be adjusted.
Oh, is the CO2 tank new so you are sure it is full?
-Mike