Quite a bit of guesswork here, but, looking at the shooting data, it suggests you were in `Exposure Mode 0`which I think is an auto setting rather than manual. If this is the case then the meter may well have picked a two second exposure if the room was pretty dark when you pushed the shutter. The low light would have caused the flash to fire, hence most stuff being more-or-less properly exposed. But, the flash only lasts around 1/1,000th of a second - and with the shutter remaining open for two seconds, the background (`ambient`) light has also hit the sensor, causing those blurs. Because the ambient light was low, they haven't made much impression.
Odd that there is no sign of flame from the candles - had he blown when you hit the shutter, perhaps?
Have a look in the manual for how to reduce the flash output, and look up `second curtain sync` as well. Then practice! This is a really tough shot to get right, so don't think it's just you, Mel.