Open blog installation problem

Hi...

I have downloaded the the latest version of open blog (i.e.OpenBlog_1.2.1) and successfully unzipped it in my root directory
that is www of wamp. and when i tried to install the open blog on my localhost it is giving me error as

"Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, admin@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.
"
plz help me