Hi,
I' ve the same problem with installation.
"Installer user interface mode not supported, unable to load and prepare the installer in GUI mode"
:(((

I think it's occurs because you try to playback not at begining position.

"But how do I send the Program Change message to this channel?"
Just select some track and open List Editor.
To add a new event to the edited part, proceed as follows:
1. Use the Insert pop-up...

Greetings.
If you want to change the instrument in the midi channel, you should send to this channel the Program Change message.