thanks everyone for your kind inputs...
Thunderbug ... i was looking at the ecam hyd page the other day when we shut down eng no.1 and no.2 was running as we were waiting to connect the ext pwr...and i can tell that what i have seen is that the green system was not pressurized ...i think it is may one of the conditions that the ptu is inhibited (look at fcom 1.29.10 p1 at the bottom ).