Not getting anything ? you should be able to change to background color as you tried, with for example : EngVar.screen_color.red.IntValue = 255;
i uploaded the new version to my homepage (It's 1.1.0.1). (I'm a bit confused right now^^)
Concerning how many times one can load the engine, i think that one can only load the engine once, because commands like engine_frame() don't take any parameters that would identify an instance.