Why can't I ...

make the Servo go both ways under program control?
This is a known bug in the compiler. Fixed in Build 130
talk to the MotorVator from my PC?
There are three specific setup values that you can alter in View>Options

A. The communications port to connect with the MotorVator. Either Tick one of COM1...COM4 or enter the name (e.g. COM5) in the OTHER box. (Note if you need this option - don't add a : to Com5). If you select a port which doesnt exist on your computer, then you will get the COM error.

Once you have selected the correct port, connect the MotorVator via the cable, power the MotorVator, and select MotorVator>Open Comms Window

This will open a Black window. The MotorVator should respond with Green text. If it doesn't, close the window and open again (Sometimes it needs two attempts).
...get a wider "Dead Band" on my joysticks
If you are using a version of MeccCompilerII before 1.31, then the Calibrate Joystick command wont work.

Upgrade to 1.31 (on the MeccCode page).
make the Action Ports turn on and off under Mode 1..6
Under Built-in Program modes 1 through 6, you can turn the Action Ports 1 and 2 on and off using the Director Buttons.

Under Mode 2, pressing Button A turns Port 1 on. To turn it off, Press Button B, which is the button within the Left Joystick. The right hand "Front button" is Button C.

It's all in the manual.