Unplanned Depreciation - ABAA - Unable to execute

Experts,

I am implementing AA.

While testing, I am unable to post Manual Depreciation - ABAA. The error " In area 01, you can only post manual dep. up to the amount 0".

The long error says" If the amount concerned is 0, this could be the result of two situations: 1. The asset does not have any net book value

(I checked, asset has a Net book value)

2. The asset has a depreciation key with automatic depreciation calculation. However, if you want to include depreciation in addition to the automatically calculated depreciation, it has to be unplanned depreciation

(How and where shall I check this???)

I am using trasac. type 640 (default). In AO90, I have defined the GL as well.

Please help. In case of any other information required, I will provide it.

Thanks

Amit