Error in Invoice thru SRM for backend Direct material PO

Hello,

I have created a PO for direct material in backend R/3.

But when i try to post an Invoice for this PO from SRM 5.0

then i am getting the error "Account determination for account account assigned PO doesn't exist for Chart of Accounts CANA".

But for the same Po if i m created Invoice in R/3 directly, it works fine and hits the correct accont.

And also my PO is not account assigned.

Also In SRM, when i simulate the accounting entries it is not getting the account number for GR/IR clearing account. it is showing a blank entry.

but in R/3 it is working fine , no issues there

Can anybody tell me wat can be the reason.

Thanks

Sarabjeet