Prepayment error!

I want to ask
why there is a warning like this when I want to include prepayment percentage?

what should I do?

I guess you didnt mention VAT Prod. Posting Group on g/l account which is used for prepayment.

I have selected the VAT Prod. Post Group, but it appears that way.

I tried to re-create PO. after all the fields filled in, I put the percentage of prepayment and it worked. But when I want to insert an item in below table, a warning appears again.

Did you set VAT Prod. Post Group for the Item which you are selecting?

yes, i did it…

but, it still appear warning again…

what must i do now?

if you can, please activate the debugger and check where exactly getting error message…

after I turn on the debugger, how do I make amends? where the main point is generally a mistake?
I do not understand the computer program

Please contact the senior in your office…

Check VAT Posting Group in Setups.

Dear Ririn,

The warning comes because there is no VAT Posting Setup for the selected VAT Business Posting Group and VAT Product Posting Group. The VAT Bus. Post. Group comes from the vendor in the purchase header and the prod. posting group from the item, or in your case from the Prepayment setup.

I know you say you checked this already, but please re-check: Because if this doesn’t work, then you should really contact your Dynamics NAV consultant to get help. End-users without prior training should not use the debugger.

In the “General Ledger Setup” please check the account “Purch. Prepayments Account”. Look up this account and check that the “VAT Product Posting Group” field has been filed out. If it has not been filed out, then fill it out and try again.

If it really has been filled out, then contact your NAV consultant.