Ok, just had to check the obvious. I had to do it twice, could not get it to work the first time, when I checked the settings the second time, some of them had gone back to default settings.
I take it you also calibrated them since programming is only the first step.
If the motors make a "beeping" noise when you apply power, then something is wrong with the settings. Motorbrake is on or something.
If this is done correctly, then it could have something to do with the trim settings.
I have never got this to work properly, if I touch the key 7-9, then the motors start going and will not stop even if I press space, which is supposed to reset the trim settings. I have to reset the browser to make it stop. If you check the manual motor settings in the ROV Cockpit the settings should be 1500 for all 3 motors and they should be still. Don't know if this helps you, but it's the best I can come up with. Maybe someone else has a better idea.