Question

There is a problem with this reference. This file can only have formulas that reference cells within

Answer 1

Problem: The lookup value is not in the first column in the table_array argument. One constraint of VLOOKUP is that it can only look for values on the left-most column in the table array.

Solution: You can try to fix this by adjusting your VLOOKUP to reference the correct column

Answer 2

Just press Ctrl+F to display the Find tab of the Find and Replace dialog box, then search for the # character. Make sure you tell Excel to do its searching within Formulas. Inspect anything that is found to see if it is an error or not. You should also take a look at any named ranges defined in your workbook.