下边是我编的一个非常简单的程序。不幸的是错得一塌糊涂（悲哀）。找了很久都不知道错在哪里。请帮忙看一下。谢谢！

*-----------------------------------------------------------------------------
*Program Name: P_2.1.SAS stored in the C:\books\learning\my program folder
*Purpose: The program reads in data on stock prices and sharesoutstanding
*and compute the value and average price and the averrage number of shares.
*Programmer: Ch
*Date Written: Feb, 2008.
*-----------------------------------------------------------------------------

data problem2_1;
        infile "C:\books\learning\stocks.txt";
        input StoCode $ Price Share;
        Value=price*Share;

run;

Title "Prob Data";
        proc print data= problem2_1;
run;


title "Summary Statistics";
        proc means data= problem2_1;
        var price share;
run;


下边是debug的信息：
52   *-----------------------------------------------------------------------------
53   *Program Name: P_2.1.SAS stored in the C:\books\learning\my program folder
54   *Purpose: The program reads in data on stock prices and sharesoutstanding
55   *and compute the value and average price and the averrage number of shares.
56   *Programmer: Ch
57   *Date Written: Feb, 2008.
58   *-----------------------------------------------------------------------------
59   data problem2_1;
60           infile "C:\books\learning\stocks.txt";
61           input StoCode $ Price Share;
62           Value=price*Share;
63   run;
64   Title "Prob Data";


65           proc print data= problem2_1;
ERROR: File WORK.PROBLEM2_1.DATA does not exist.
66   run;

NOTE: The SAS System stopped processing this step because of errors.
NOTE: PROCEDURE PRINT used:
      real time           0.00 seconds
      cpu time            0.00 seconds

67   title "Summary Statistics";


68           proc means data= problem2_1;
ERROR: File WORK.PROBLEM2_1.DATA does not exist.
69           var price share;
ERROR: No data set open to look up variables.
ERROR: No data set open to look up variables.
70   run;

NOTE: The SAS System stopped processing this step because of errors.
NOTE: PROCEDURE MEANS used:
      real time           0.00 seconds
      cpu time            0.00 seconds


我起初以为是文件路径错了。但经检查没错，我真的百思不得其解，望指点迷津。谢谢！