Account Assignment mandatory for Material no. 1417

Hi all,

Need a help in creating a purchase order. I have Integrated everything with MM, entire configueration is done but when i try to raise a PO it asks for Account Assignment (i have not created cost centeres yet), I gave Unknown as account assignment but again it says that Unknown is not correct for your purchase order, when i give Order as an account assignment it asks for the GL a/c no.

Pleaese suggest me how to get thru this and create a PO.

What is account assignment?

Why does system ask for the GL account number at the time of creation of PO (because creation of PO will have no effect in GL accounts so why to give GL accont no)

Pleaes help.

Thanks in advance,

Kamal