There are 3 major contributor's to making the Accuris skip.
1.  The air hose.
2.  The bearings the laser head rolls on.
3.  The X motor gear being loose or stripped.

1.  For the hose, what you want to do is put the laser head in the center, all the way at the back of the machine.  This will put the laser head really close to where the air hose connects to lid of the laser.  What you are looking for is spaces between the coils of the hose.  If there are spaces between the coils then the hose will need to be replaced.  What could be happening is as the laser head swings back and forth, if the hose can not recoil properly it can pull the laser head off of position.  In the white box that came with your machine there should an additional hose.  You can replace your hose with the new one or purchase a new one.  The part number is P-ACC-A600800200.  The new one may have extra long ends on it, you will want to cut those off.  Do your best to make the new hose look just like the one that is currently in your machine.  
Once installed you can put the laser back into this position any time the laser is going to sit for any length of time (1 or more hours and over night).  This will allow the hose to remain coiled and recoil correctly.  You can set your P1 or P2 position button to this point, so we just have to hit it before turning it off or after each job.   

2.  The bearings (rollers) on the laser head.  There are 2 bearings on the top and 1 bearing on the bottom.  You need to visually inspect all 3 and ensure that none of them are dirty, burnt, stuck or anything like that.  If they are dirty, clean them until they move freely again.  If they are damaged, you will need to replace them.  You will also need to clean the tracks that these bearings roll in (top and bottom).  With the machine off, you can move the laser head back and forth inside the machine, it should be a very smooth fluid motion as it moves across the table.   You should be able to move it with 1 finger and not alot of pressure. 
You can compare it to the move of the rail forwards and backwards in the machine.  They should be equally smooth and fluid.  

3.  The X motor is located on the right hand side of the rail.  It is the silver square, with the 4 screws.  One screw in each corner.  This picture is a side view of the motor.  The gear on the bottom is where the belt wraps around and moves the laser head left and right inside the machine. 

You will need to use the alan wrenches that came with your machine (the smallest one) and tighten the set screw on the collar. 

The easist way to access this is to pull the rail all the way to the very front of the machine.  Put your head inside the machine, where your head is up side down.  You will look between the motor and the rail the laser head rides on. You will see where the belt wraps around the gear on the bottom.  With the machine off, you can move the laser head left and right inside the machine and rotate that gear around.  Rotate it until you can see the set screw, use the alan wrench to tighten it. 

Take a look at these 3 things and if it doesn't resolve your issue, let us know.