Astra Estate boot opens when i turn ignition?

Can anyone solve this problem??

I own an Astra Estate Design on an 07 plate and today when i pushed the unlock button on my key fob the boot mechanism went into a spasm and opened the boot. I thought it was just a oneoff but it hapens all the time now.
ALSO.... when i put the key into the ignition and turn it to start the engine the boot mechanism does exactly the same thing and opens up the boot!! I have to go to the boot before i set off and hold the soft pad to make the boot close properly!!

Any Ideas what the problem is??????????

Darren Quinn
February 2011