error 500

i have installed restaurant j2.5 on my host server
i want instal the component hikashop or virtumart but every time when i try the error 500 internal server error appears:

" Internal Server Error
>
> The server encountered an internal error or misconfiguration and was
> unable to complete your request.
>
> Please contact the server administrator, [email protected] 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.t. "

What is the problem ?

i have installed on the real design and there its working fine

Please check the server error log or contact with your hosting company to get more details because as you can see this message tell only that some internal server occur but without additional details.