Beaters will not move

Push up and twist at the same time.

If it is a ksm103 there should be a spring on the shaft, it should look similar to this: http://www.mendingshed.com/kacentershaft.html

When adjusting the screw you should be turning it out, which will make the beater closer to the bottom of the bowl, when properly adjusted you should be able to place a dime in the bowl, and the flat beater should just move it around barely. that would be about 1/16" in clearance.

Use a small amount of vegetable oil to lubricate the beater shaft and
the beater. Slightly tap the beater up and sideways with a rubber mallet
until you can move the beater easily along the shaft.

Make sure your Beater can slip in and out of the Beater Shaft
easily. Do not force the beater onto the Shaft if the shaft is bent.
If it cannot be removed easily by hand, use a soft rubber mallet
(not a steel hammer) to slightly tap the beater so it can be moved
up and down the shaft or from side to side. Then you can easily
turn the beater left and remove it from the shaft.

From Kitchenaid Manual:
To Attach Flat Beater, Wire Whip, or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Slip beater onto beater shaft and press upward
as far as possible.
5. Turn beater to right, hooking beater over pin on shaft.
6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft

Make sure your Beater can slip in and out of the Beater Shaft

easily. Do not force the beater onto the Shaft if the shaft is bent.

If it cannot be removed easily by hand, use a soft rubber mallet

(not a steel hammer) to slightly tap the beater so it can be moved

up and down the shaft or from side to side. Then you can easily

turn the beater left and remove it from the shaft.

From Kitchenaid Manual:

To Attach Flat Beater, Wire Whip, or Dough Hook

1. Turn speed control to OFF.

2. Unplug stand mixer or disconnect power.

3. Tilt motor head back.

4. Slip beater onto beater shaft and press upward

as far as possible.

5. Turn beater to right, hooking beater over pin on shaft.

6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook

1. Turn speed control to OFF.

2. Unplug stand mixer or disconnect power.

3. Tilt motor head back.

4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft.

Make sure your Beater can slip in and out of the Beater Shaft
easily. Do not force the beater onto the Shaft if the shaft is bent.
If it cannot be removed easily by hand, use a soft rubber mallet
(not a steel hammer) to slightly tap the beater so it can be moved
up and down the shaft or from side to side. Then you can easily
turn the beater left and remove it from the shaft.

From Kitchenaid Manual:
To Attach Flat Beater, Wire Whip, or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Slip beater onto beater shaft and press upward
as far as possible.
5. Turn beater to right, hooking beater over pin on shaft.
6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft

Your beater to bowl clearance has come out of alignment. This can happen naturally over time and with normal use of the appliance. This is something you may correct from home using a flathead screwdriver.

Unplug the mixer, with the bowl and flat beater removed. Tilt the mixing head back as far as the machine will allow. In the exposed hinge, behind where the bowl would normally sit, you will see a 3/8 screw exposed. Turn this screw half a turn counterclockwise (to your left) in order to raise the flat beater from the bottom of the bowl.

This may take a few attempts until the beater is clearing the bottom of the bowl again. If the adjustment screw will no longer turn, do not force it. It is only designed to move so far to make the appropriate adjustment.

Be cautious. Raising the flat beater too high may leave dry ingredients at the bottom of the bowl.

If further information is needed, I would advise you to contact Kitchenaid Customer Service. They may walk through this adjustment through you over the phone and can look into ordering replacement beaters for you also.

Their toll-free telephone number is 1-800-541-6390.

if you remove the top you will find a tiny fuse wrapped in a black band on the left side from the back. It connects two white wires which power the top-side motor brush. Most likely this needs to be replaced. You can check by bypassing it with roach clips or a copper wire. Unplug the machine first and be careful!

I took the advice from: http://forum.kitchenaid.com/forums/topic.asp?TOPIC_ID=6356
I put a wash cloth in a pot of boiling water and used tongs to wrap it around the beater shaft while the mixer was resting on its side. When the wash cloth was not too hot to touch, I put it back in the boiling water and did it again. I was then able to easily remove the beater.

Try a higher speed , this should force the batter out using the centrifugal force generated