I've been to my dealer 3 times with the same problem on my 10500 mile 2007 LS and I'm relieved to hear that I'm not the only one with this problem.
The first time the dealer could find nothing wrong with the doors (it's mainly the driver's (RH drive) door that's worse) as the fault typically disappeared. They simply sprayed the runners with silicone grease
The second time they had the car the fault showed up twice in 30-odd operations and they could not find a source for the fault. However as I was picking the car up a mechanic was taking photos of the seat covers (material bobbling badly on all seats) when he had problems closing the door for about 20mins. Booked car in again.
The last time they had the car they managed to replicate the fault 8 times out of ten

.............
here's the reason according to them....
......
in the manual it states that if the vehicle is on an incline of greater than 15% the safety override cuts in to open the door.
This override detects the door travelling either too slow (something holding the door back) or too fast (runaway door).....according to the dealer.
I was told to park my car on the straight and level and when I told them that my drive was on a slope and what should I do they said to close it with the power switch off.....

Whats the point of having electric doors then????
To add to this we have a 4 year old and 5-month old twins so both doors are in use - the other day my wife struggled for 15 mins to get the door to shut safely outside the village primary school....in the pouring rain on a busy road.....a road which is on the straight and level.
Since the third visit we have had the problem on numerous occasions.
The crunch is that it doesn't do this all the time......only 99% on the drivers side and also it often closes fine when on a slope.
This says to me that there is something wrong somewhere with this vehicle. I notice from the earlier posts that Kia are aware of this (March 07) -
Does anyone have any more info on this please? My next step will be to send a snottagram to Kia UK as we have had other faults with our car (seat cover wear, front wheel judder, new tyres at 10k and poor fuel consumption) and I feel were getting fobbed off.
Any help would be very welcome.