I am afraid that I cannot help you with your electrogoniometer, either with or without direct flexion feedback, but maybe we can get the LCD working with something simple and then someone can help you print your serial data.
First we have to know exactly what kind of LCD you are using. Is it using the 14 or 16 pin parallel interface directly or are you using some sort of serial interface. A link to the datasheet for the device would be helpful, especially if it uses a serial interface.
We also have to know exactly which libraries you are attempting to use. You did not include that part of your program. By the way, when you post code you should highlight that code with your mouse and then press the 'Code' button, it looks like a # symbol.
So, unless you have already done this, you should start with something simple like the 'Hello, world' example which comes with the LiquidCrystal library.
Don