THIS COME UP FOR ALL MY ITEMS. PLS HELP FIND A SOLUTION. THANKS 
From what I can see of the error message, it looks like you have an invalid foreign key value in the Sales Line table, specifically, in the VAT Product Posting Group field. In the Sales Line, you have the value VAT25 in this field. The problem is that this field is related to the lookup table “VAT Business Posting Group”, and the value that you have on the line (VAT25) doesn’t exist in the lookup table.
So, you have two issues to investigate. The first is to determine how that condition came to exist. The second is to decide how to fix it.
There are any number of ways that this could have come to pass, but my likely first guesses would be that either the value in the lookup table got deleted or renamed, or the value on the line got set through some method other than the normal data entry page (through import or other program code.) That will be for you to determine.
The fix is easy enough. Decide whether VAT25 is a valid value, and edit your data accordingly. If it’s a valid value, create that record in the lookup table. If it’s not valid, delete that value from the sales line.
Hope that helps.