mysql 存储过程问题调用时候报错?报错

请帮忙看一下为什么会报错,小弟首次编写这种类型的存储过程:
delimiter $$
create procedure mydb()
begin
declare dbname varchar(50);
declare stop int default 0;
declare cur cursor for (select name from name); //name表中存放的是数据库的名称 
declare CONTINUE HANDLER FOR SQLSTATE '02000' SET stop = null;
open cur;
fetch cur into dbname; //遍历数据库的名称
while ( stop is not null) do

begin
declare name varchar(200);
declare stop1 int default 0;
declare cur1  cursor for (select prounit_name from dbname.prounit);  //获取prounit表中prounit_name字段内容
declare CONTINUE HANDLER FOR SQLSTATE '02000' SET stop1 = null;
open cur1;
fetch cur1 into name;
while ( stop1 is not null) do
    update prounit set name='abc';
    fetch cur1 into name;
end while;
close cur1;
end ;

fetch cur into dbname;
end while;
close cur;
end ;
delimiter $$

在执行存储过程error:ERROR 1146 (42S02): Table 'dbname.prounit' doesn't exist

why?????