hierarchyviewer on a real android device

[rlolage]

I am writing some automation to control the device using java.
I am using tool called hierarchyviewer provided by android sdk..
Also i am using chimpchat and hierarchyviwer libs in my java project...

I am doing the following call
hierarchyviewerobject = device.gethierarchyviewer;

By doing this i grab the view nodes in the current activity and then their properties.

The above call works like a charm on emulator. But fails with the following error on a real device
Unable to debug device (device id)

Is there a way to make this call on real device?

Any help would b appreciated.
Thanks.