issue with order hooks

[mike099]

My website is in 1.7.2.4 ,I have tried this hook on my custom module:-displayOrderConfirmation. This hook is working without any problem. However there is an issue when I am trying to use any of the following hooks (which in same module):-
1) hookActionProductCancel
2) actionOrderStatusUpdate
3) actionOrderStatusPostUpdate

There is no single hook working from above mentioned,I am adding it proper rule,
Here is example of my code:-

Step1:-
$this->registerHook('actionProductCancel')
$this->registerHook('actionOrderStatusUpdate')
$this->registerHook('actionOrderStatusPostUpdate')

Step2:-
public function hookDisplayOrderConfirmation($params){}
public function hookActionOrderStatusUpdate($params){}
public function hookActionOrderStatusPostUpdate($params){}

I am testing all above hooks from admin panel by chanding status of order,But not working any hook.

Let me know I need it on urgent basis.

Thanks!!