[TYPO3-english] How to fix "Could not analyse class: "Tx_Vhs_ViewHelpers_Page_HeaderViewHelper"

[james xu]

we are using typo3 which version is 6.26 and VHS is 2.0.2. now we want to upgrade VHS to 2.4 , after install this version by extension manager,  "Oops, an error occurred! Code:xxxx". and the log shows "Could not analyse class: "Tx_Vhs_ViewHelpers_Page_HeaderViewHelper" maybe not loaded or no autoloader? Class Tx_Vhs_ViewHelpers_Page_HeaderViewHelper does not exist
 exception code:1289386765 file:/typo3/sysext/extbase/Classes/Object/Container/ClassInfoFactory.php line:37

trace:
file: /typo3/sysext/extbase/Classes/Object/Container/Container.php" line:349 function:buildClassInfoFromClassName
file: /typo3/sysext/extbase/Classes/Object/Container/Container.php" line:173 function:getClassInfo
file: /typo3/sysext/extbase/Classes/Object/Container/Container.php" line:126 function:getInstanceInternal
file: /typo3/sysext/extbase/Classes/Object/ObjectManager.php" line:99 function:getInstance
file: /typo3/sysext/fluid/Classes/Core/Parser/TemplateParser.php" line:560 function:get
file: /typo3/sysext/fluid/Classes/Core/Parser/TemplateParser.php" line:536 function:initializeViewHelperAndAddItToStack
file: /typo3/sysext/fluid/Classes/Core/Parser/TemplateParser.php" line:509 function:openingViewHelperTagHandler
file: /typo3/sysext/fluid/Classes/Core/Parser/TemplateParser.php" line:357 function:buildObjectTree