Class not registered in IE7

Every time when i open my IE7, and browsed certain pages, the browser will showed "Class not registered" javascript error. Open a command window, and try re-registering the IE dlls with a batch file like this:

regsvr32 c:\windows\system32\urlmon.dll
regsvr32 c:\windows\system32\actxprxy.dll
regsvr32 c:\windows\system32\shdocvw.dll
regsvr32 c:\windows\system32\mshtml.dll
regsvr32 c:\windows\system32\browseui.dll
regsvr32 c:\windows\system32\jscript.dll
regsvr32 c:\windows\system32\vbscript.dll
regsvr32 c:\windows\system32\oleaut32.dll
Then, it works fine. Good Luck.