i may be misunderstanding your setup. are you saying you have tubing between the co2 tank and the solenoid? if so, that's not gonna work. everything before the solenoid has to be able to handle the pressure being put out by the regulator. that's why the solenoid is typically threaded directly into the regulator.
it also looks like you might be using standard airline tubing, which isn't designed to handle much pressure at all.