The visitors cannot see my albums, when thy click on any album to view it, they get 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, webmaster@photo.fsoly.com 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 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Probably you have modrewrite enabled and you server does not support it or you did not upload the .htaccess file. Setup should have told that.

Also, some servers will "choke" on urls with special characters in them. Be sure you albums and images are simple ascii text.

There is no problem with server
And I uploaded .htaccess file
And the images has simple ascii name

So what is the problem? and how can i fix it?

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

Please contact the server administrator, webmaster@photo.fsoly.com
and inform them of the time the error occurred, and anything you
might have done that may have caused the error.
`
This really is a contradiction to your statement that there is no problem with the server. It is not an error produced by Zenphoto. I suggest you follow the directions in the message and contact the server administrator.