My b2evolution Version: Not Entered

I went to 'View Default Page' and when i click 'Add A New Blog', this came up:

The website cannot display the page
HTTP 500
Most likely causes:
The website is under maintenance.
The website has a programming error.

What you can try:
Refresh the page.

Go back to the previous page.

More information

This error (HTTP 500 Internal Server Error) means that the website you are visiting had a server problem which prevented the webpage from displaying.

For more information about HTTP errors, see Help.

CAn some one help please.