No line items..

I am held up with an issue.

Internal Order has been settled to AUC and there are two items available i

I am executing an AuC settlement to fixed assets using Tcode AIAB. Distribution rules have been entered. Asset class (AuC) has already been created with 'line item settlement'. However while executing the AIAB system throwing a message that 'asset has no line items to settle'. Where could I am be going wrong ?

Regards