Something would be amiss even if the red/white ignition(injector) live wire wasn't connected properly... The amber light shouldn't be on all the time.
Would check wiring first as Brian says. Presuming good lives and earth the next step would be trying another ECU/switch - far easier if you have them on the shelf of course!
Seen similar comms symptoms when incorrect firmware has been uploaded. Also when ECU has been jetwashed...
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
2 miles A1, 8 miles M62, http://www.Lpgc.co.uk