As the subject says,
I am trying to get Soft-15KHz to work on my computer to arcade, but so far It hasn't worked.

I've installed Soft-15KHz to my Windows 7 system, I have the most up to date drivers for my GeForce 6200(ForceWare v 137.83), and I also set my resolution to 640x480 with QRes.
I turned off my CPU, plugged in the VGA to my JPAC, to my Jamma Harness, and I get video on my CRT. The problem is that it's a screen and a half.
I don't get any lights lit up on my JPAC, so I assume it's not sending the 15KHz signal correctly.
Is this a known issue? Any help would be lovely.
Pictures for reference:
http://imgur.com/a/8YMcm