VLOOKUP absolute beginner, quick help please

I have a workbook comprised of 20 or so worksheets, there is a VLOOKUP formula on the worksheet (titled 'data') with sellout totals which points to the price list worksheet which has the most recent prices, at the end of every quarter we get a new price list with updated prices for some products, so in the past I have either added the updated prices to the that worksheet (e.g. PL 2014 Q4), then deleted the rows with the old prices or copied and pasted the 2014 Q4 price list in to a new worksheet which is then named PL 2015 Q1 and so on..

In the past the VLOOKUP formula has worked fine on the worksheet titled data, but because we recently expanded our product line, we have many new SKUs which I have spent the last week adding to the new worksheet (titled 'PL 2015 Q1')
The formula works fine on the older SKUs, (black text, first three rows) but does not work on any of the new ones (green text, bottom 4 rows) - I have added a screenshot to illustrate:

VLOOKUP Question.JPG