各位朋友，Mplus跑出来的结果，为啥老是出来这个结果，请帮忙看一下。模型是X-M-Y,W调节第二阶段，其中X和W在第二层。新手上路：

INPUT INSTRUCTIONS

  DATA:

    FILE IS C:\Users\14981\Desktop\SSSSS.dat;

    DEFINE:

    CENTER W(GRANDMEAN);

    CENTER M(GROUPMEAN);

    MW=M*W;

  VARIABLE:

    NAMES ARE sex old marry edu tenture level cluster X M W Y;

    USEVARIABLES ARE old marry edu tenture level X M W Y MW;

  CLUSTER=cluster;

  WITHIN=M;

  BETWEEN=X W MW;

  ANALYSIS:TYPE=TWOLEVEL RANDOM;

  MODEL:

  %WITHIN%

    Y on M;

  %BETWEEN%

    M on X;

    Y on M

    X W MW old marry edu tenture level;

  OUTPUT:SAMPSTAT;

*** WARNING in DEFINE command

  The CENTER transformation is done after all other DEFINE transformations

  have been completed.

*** ERROR

  One or more between-level variables have variation within a cluster for

  one or more clusters.  Check your data and format statement.

     Between    Cluster ID with variation in this variable

     Variable     (only one cluster ID will be listed)

      X          24

      W          24

      MW         24

能否帮我看看WARNING和ERROR的原因么？我觉得我是按照书上做的，不知道为啥出现这个。。。