Update 2.0.0 to 2.1.0

I have joomla 2.5.9 and when I try to update hikashop essential 2.0.0 to 2.1.0 appears this message:

Internal Server Error

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

Please contact the server administrator, This email address is being protected from spambots. You need JavaScript enabled to view it. 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.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Hi,

Have you access to the server error log file ? Could you give us the returned error ?