Firmata Servo Control

Good day

I am working on a robotic tank with CO2 airgun, but I am now stuck. Please follow this link to see what i would like my firmata control window to look like. I am curently using the Old Standard Firmata Library, as the normal Standard Firmata Library is not working on my Arduino Deumlanueve, and i am controlling my 2 servo's on Digital pin 9 & 10 (pan/tilt). This works, but the servos are jumping all over the place, and gears are creaking inside the servo housing. I am currently using this app, because you have the option to choose COM port & BAUD rate, so just by using the top section of this app & creating 4 buttons to pan & tilt a servo will be awesome

Please, can someone create or similar app for me to controll my to servos using any c#, or any other Windows XP compatable code and the scetch to control my Arduino via my PC's USB port.

Here is an example of another app, but this only support the control of 1 servo on pin 9 or 8.

Please help me with this.

Thank you & regards

Riaan Deyzel