Client will not install when cmd line switches used

I have generated a new client to push manually to several systems. Our companies requirements dictate that this be a completely silent install, which with /QN should not be an issue.
We have done it plenty of times in the past. But with this newest client, no matter what command line options I use, for example, Setup.exe /qn /L*V C:\log.txt

Nothing happens. Ever. But if I just type setup.exe poof it is off and running with minimal gui. I have tried all manner of the command line switches, alone and in groups.. it never runs on any test boxes, with any of them.

What am I doing wrong?