Shots 1 and 2 look to be out of the strobe range to me, remember your strobe is good to maybe 8 ft max, 6 is more realistic. If shot 3 was shot with telephoto it is too far also. I see no shadows or other signs of strobe other than some backscatter in photo 1. If your shooting at greater distances than your stobe is capable of your better off turning it off and setting the white balance manually. I would suggest you pan out as wide as your camera will go and get closer to fill the frame.
If the 2000 is like the 180, shooting in manual mode the magnet should be out and the internal flash set to slave. Shooting in aperature priority it should be in.
If the 2000 is like the 180, shooting in manual mode the magnet should be out and the internal flash set to slave. Shooting in aperature priority it should be in.