Just for anyone running into this.
Make sure you include MPU6050 (folder) and I2CDev (folder) in your libraries for arduino (Usually User/MyDocs/Arduino/Libraries)
If you've done that and are still throwing errors, make sure you're using the right arduino.exe (yes you can have more than 1 installation).
My issue occured when I opened the wrong arduino and dragged in MPU6050 into an empty window. This made the project "sketch_todays_date" instead of MPU6050. The program was therefore processing out of the wrong window. You want to make sure that MPU6050 is the only thing there / have the right pathing etc.