CI，session加载错误

新换了服务器后出现如下错误：

A PHP Error was encounteredSeverity: Warning

Message: mkdir() [function.mkdir]: Invalid argument

Filename: drivers/Session_files_driver.php

Line Number: 117

Backtrace:

File: E:ampapachehtdocsmvcapplicationcontrollersuser.php

Line: 75

Function: library

File: E:ampapachehtdocsmvcindex.php

Line: 292

Function: require_once

An uncaught Exception was encounteredType: Exception

Message: Session: Configured save path '' is not a directory, doesn't exist or cannot be created.

Filename: E:ampapachehtdocsmvcsystemlibrariesSessiondriversSession_files_driver.php

Line Number: 119

Backtrace:

File: E:ampapachehtdocsmvcapplicationcontrollersuser.php

Line: 75

Function: library

File: E:ampapachehtdocsmvcindex.php

Line: 292

Function: require_once

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解决方法，修改application/config/config.php中设置：

$config['sess_save_path'] =BASEPATH.'../'.'session_file';