Error while ship confirm the order line

Hello All,

I have an item which is setup as follows,

from inventory tab,it is only 'Reservable' and from Order Management tab it is setup as shippable,customer ordered mainly.

Know when the order line is entered,the subinventory was specified,which is causing the issue while ship confirming the delivery for this order line.(after picking the line).

When the item in not stockable ,do we need not to specify the subinventory in order line.

Please Advice.

Thanks

Deepak