Error Cannot Retrieve tax Information in P.O

Hi all,

I am Using SAP B12005B PL40.

I am facing the Error - Cannot retrieve Tax Information In P.O. while saving It.

I have Entered 5 Row Level items in the P.O. with all Related to same BED Tax Code.I have set approval Procedure also For This.Once this PO is Generated by the user Approval Procedure is enabled.Later after all approval Procedure is completed.Ultimately when the user is about to save the PO.Two Messages are displayed .

Message 1.

This PO Will Create Subbordinate PO.

After Giving OK To this message.

Message 2

Cannot retrieve Tax Information.

and it doesn't allow PO to Get Saved.It Remains still in the draft mode.

Why?????????

I have enabled Excisable Check Box For all those items in the Item master.

Thanks in Advance,

M.Badrinarain.