Think you just got your quotes messed-up a bit, try this untested revision to your script:

Break On

If INGROUP("KS1")
 use X: \\SCHOOLNT\KS1DESKTOP
 del "C:\DOCUMENTS AND SETTINGS\"+@USERID+"\DESKTOP\*.*"
 copy "X:\*.*" "C:\DOCUMENTS AND SETTINGS\"+@USERID+"\DESKTOP"
 use X: /d
 AT(3,4) "KS1"
ENDIF

If INGROUP("KS2")
 use X: \\SCHOOLNT\KS2DESKTOP
 del "C:\DOCUMENTS AND SETTINGS\"+@USERID+"\ALLUSERS\DESKTOP\*.*"
 copy "X:\*.*" "C:\DOCUMENTS AND SETTINGS\"+@USERID+"\DESKTOP"
 use X: /d
 AT(3,4) "KS2"
ENDIF

AT(5,4) "RAN"

exit


Hope this helps

-Shawn