Hi,
1) Find country code for your tax procedure assigned in t.code:OBBG
2) What tax code you are entering in purchase order and find your company code which you entered purchase order creation. Now check did that tax code created for that your company code with country code in t.code: FTXP.
3) Tax condition type used for your tax code and find did that tax condition type assigned to Condition exclusion indicator(OBYZ- condition types) or any Routine assigned to tax condition type in tax procedure (OBYZ- procedures) which cause your concern
4) Did you are entering correct tax code in purchase order and is your tax code is a INPUT TAX
5) Excise rates segment and validity period set with Chapter ID in t.code:J1ID.
6) Check Tax jurisdiction code mainatined in Plant.
7) check validity of the condition records in FV13
8) check is your tax code is assign to company code, also check classify condition type.
Thanks
Mahesh Naik