I seem to have solved the problem. I wasn't aware of the difference in the number of pins, and I started looking closer at the bottom of the flash. I think I didn't do a good job of lining the pins up between the hot shoe and the transmitter. I have a better fit now and it seems to be working...
I am trying to use an external flash with a wireless transmitter. The transmitter goes into the hotshoe fine. The issue is that the on-board flash tries to pop up and can't, because the transmitter is in its way. However, this keeps the flash from firing; the flash light (lightening bolt) is...