hi all
i managed to solve the prob.
Drove the car back to tan chong bukit timah and the technician told me that when i shifted my gearbox to "P", the immobiliser doesnt recognise that the gearbox is in "P", which is why the car cannot be started. This happens due to wear and tear (not covered by warranty) as the cable linking the various modes of the gear box (eg: PRND12) may suffer some free play in movement after using the car for some time. This results in the sensor in the car not correctly recognising that the car is in "P" position, even though the gearbox has been shifted to "P".
The solution: if you have problem cranking up the engine, try to push up the gear level (yes it is in P position, but u can still try to "push" it up further) with your left hand while your right hand is cranking up the engine. It works =)