Connecting the J-Pac

PC came in within a week after ordering, so I decided to quickly test the setup. Simply connected the keyboard and vga-inputs on the J-Pac and plugged it in the JAMMA interface, but it didn't fit.
So picked up a small kitchenknife and started scraping the J-Pac. After a few minutes, it fitted!

Now it was the real test, and I booted the PC and...