The line you highlighted does not superficially appear to have an error. The quotes balance as far as I can tell. So do the parentheses. (May I suggest a different color highlight for future reference? Yellow on white is VERY hard to read. Blue, green, red, or purple work just fine.)
Like CJ, I don't know what you are asking. But if I had to hazard a guess, I would say that your NZ() function is missing a second argument. The first is obviously the DLookup, and that is good as-is. However, if you want to do a text comparison, it would be good to assure that you get back "" (an empty string) from the NZ if there is something wrong with the lookup.
I have one other minor quibble. Your method of obtaining the username is a bit off, maybe. I always use Environ("Username") when in a domain-based environment.