(本站长是以下面的报错找到了以下答案，因此改正）

PHP Warning:  Unknown: open(/tmp\sess_8gtvmjolnapmrabqdjrbqvrf27, O_RDWR) failed: Permission denied (13) in Unknown on line 0
PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0

错误提示：Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at E:phpcodeadmin.php:1) in E:phpcodelogolistadminlogo.php on line 2

解决办法,修改php.ini中的session.auto_start = 0 为 session.auto_start = 1

重启IIS调试!如果还提示以下类似的警告

Warning: session_start() [function.session-start]: open(/tmp\sess_84cb589ea249708b09c3d5e6836fdd0d, O_RDWR) failed: No such file or directory (2) in E:\web\htdocs\111.php on line 9   

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at E:\web\htdocs\111.php:8) in E:\web\htdocs\111.php on line 9   

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at E:\web\htdocs\111.php:8) in E:\web\htdocs\111.php on line 9   

test222.php   

Warning: Unknown(): open(/tmp\sess_84cb589ea249708b09c3d5e6836fdd0d, O_RDWR) failed: No such file or directory (2) in Unknown on line 0   

Warning: Unknown(): Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0  

就是 session变量需要系统的临时空间,session.save_path = "设置一个有效文件夹的绝对路径" ,(比如 session.save_path = "C:\WINDOWS\temp" )

session.save_path =前面的 ' ; '号去掉 ,另外编辑该文件夹的权限 添加EVERYONE 有写入修改权限即可 !