Could someone please explain why I am getting white, semi-transparent dots for night photography with flash on?
Original image here.
Looks like there was some dust or watter droplets or whatever in the air and that they reflect the flash light. The effect is not very present but as your background is black you can see them. Furtehrmore as they are out of focus they appear as disc rather than dot (in fact you got nice bokeh)
To me it looks like a dirty lens?
Fingerprints on the front lens (especially of a point and shoot) look exactly like this photo. The light from the flash bouncing back from the perimeter of the lens at high angles will emphasize them. You are not actually seeing the oil from the print itself, you are seeing the high angle light refracted by the shape of the oil on top of the lens. Since this light is grossly out of focus, the points look larger due to bokeh. The brighter the light, the larger the "spot".
It certainly looks like dust in the air - one other thing to check is that your sensor is clean - you can buy kits to clean the sensor from probably all camera shops.
When you use one, REMEMBER! BE GENTLE WITH YOUR SENSOR :)