So you're saying if you block the eyes the gun still won't fire? But if you turn the eyes off the gun will fire?
That sounds like bad eyes, low battery power, the eyes are plugged into the wrong spot on the board(if there even is another spot), or the board is defective. Try a board reset to see if that helps.
Now It's been a long long time but if I remember turn off the marker. Put dip switch 2 on then power up and you'll be in program mode. From here just hold the trigger down for about 10 seconds until it flashes all colors. Then let go and that should return all settings to stock. Then power the gun off and on again to see if that helps.
One other thing to check is that the wires that go to the eyes are not broken off....and that they are all the way down into the white wire plug on the board. Sometimes people yank on the wires and pull them out of the white plug, which means they won't work properly. Even bad eyes will usually cause the gun to fire if they were plugged in properly. Yours don't so either the eye wires are messed up or the board is.
I would try a new battery from another pack too. If there isn't enough power to run the eyes, and board at the same time, the gun may still fire without eyes on. It would die shortly though. It's worth a shot, you may have just bought a pack of duds.
Last but not least, if none of the above works out call virtue. They may still replace it if they have any in stock.
It's all about the angles.