Hello,
Double check what was suggested to you before regarding page length:
(not sure if I missed you mention the exact model I'm assuming you have a CE500)
-PAUSE, NEXT until you see Page Length, ENTER set to 1196in ENTER,-
then press NeXT until you see Command, ENTER, GPGL, ENTER, MAKE SURE YOUR Step Size setting is the same as in CM2 or 254.
In CM2 check the Step Size setting by clicking on the Adv. tab, Step size and again make sure you have it set to exactly what is on the plotter, this step size setting if its not matching will mess w/ the scale of you job.
Now, after confirming this. Do not scale or resize your job w/ in CM2- always try to work w/ the exact sizes right out of your Adobe Ill. When you open CM2 the job size should be the same as in your design- if its not this is normal because if you have a weed border activated it will take that into account on the job size. Remember you can always load the Pen that came w/ the plotter, and turn your vinyl upside down and plot on the white backing to see or practice how you job is going to come out that way you dont waist to much material troubleshooting.