请教各位大侠：

为什么我编写的这个程序运行不了：

options nodate pageno=1 linesize=80 pagesize=60;
data piesales;
input Bakery $ Flavor $ Year Pies_Sold;
datalines;
Samford apple 1995 234
Samford apple 1996 288
Samford blueberry 1995 103
Samford blueberry 1996 143
Samford cherry 1995 173
Samford cherry 1996 195
Samford rhubarb 1995 26
Samford rhubarb 1996 28
Oak apple 1995 319
Oak apple 1996 371
Oak blueberry 1995 174
Oak blueberry 1996 206
Oak cherry 1995 246
Oak cherry 1996 311
Oak rhubarb 1995 51
Oak rhubarb 1996 56
Clyde apple 1995 313
Clyde apple 1996 415
Clyde blueberry 1995 177
Clyde blueberry 1996 201
Clyde cherry 1995 250
Clyde cherry 1996 328
Clyde rhubarb 1995 60
Clyde rhubarb 1996 59
;
proc chart data=piesales;
vbar flavor/subgroup=bakery;
sumvar=Pies_Sold;
title ‘Pie Sales by Flavor Subdivided by Bakery Location’;
run;

log里的提示是

168  sumvar=Pies_Sold;
     ------
     180
ERROR 180-322: Statement is not valid or it is used out of proper order.

我的sas 版本是8.2

请大家帮帮忙，多谢多谢