为什么会提示：*** ERROR  The input file does not contain valid commands:
  c:\users\i-ales\desktop\mptext1.inp
命令如下：

INPUT INSTRUCTIONS

  Title:
    潜在类别分析
  Data:
    File is C:\Users\i-AlEs\Desktop\lca_1.dat;
  Variable:
    names        = id economy volunteer entertainment politics housework;
    usevariables = economy volunteer entertainment politics housework;
    categorical  = economy volunteer entertainment politics housework;
    classes = c(4);
  Analysis:
    Type=mixture;
    starts=200 50;
  Plot:
    type is plot3;
    series = economy (1) volunteer (2) entertainment (3) politics (4) housework (5);
  Savedata:
    file is lca1_save.txt;
    save is cprob;
    format is free;
  output:
    tech11 tech14;