Hi Gabriel, look in your Fantom Editor, And tell me what you have listed in the inputs and outputs of setup. You should have Fantom VS (VS700) listed in all four spots. It's usually a input output problem. Same thing with your track inputs and outputs. Whether or not you are using 64 bit 0r 32 bit. Look in your midi devices and make sure your midi devices are enabled, ei., your midi keyboard, midi router if you're using one, Fantom VS (VS-700), IO Midi (VS700). Uncheck ARX, DV-7, V-Link.
Also list what Sonar version you are using, What Windows version. After that we'll update your instrument definitions and some other stuff and make it work better.