Did you bother to read (google) the meaning of a 500 error?
in reply to CGI Script Working fine from my command prompt but Shows Internal server error when called through browser
Have you read your server log?
Under what ID is the server running your code? (Hint: it's likely not the same ID as when you exectue the code from the command line).
Really important hint: read the instructions around the text entry box! They tell you to wrap your narrative in <p>...(narrative goes here) </p> tags... and your code (so we can read it conveniently) in <code... (code here) </code> tags.