Error Connecting PIC12F683 to MPLABX with PicKit3
Is your device getting dc power? (That's what target voltage VDD means).

In your MPLAB project properties, there's a setting which determines whether the PicKit should supply the power (as indicated by your schematic), or not (i.e the power comes from your board's own power connection).   It might be set wrong. 

If your board has a lot of other parts on it besides the microcontroller, it's  possible that it needs more current than the PicKit can supply,  so you might need to use a separate power supply (and set the project setting accordingly).