Missing 404 error

[Plazik]

Hello.
If the gallery no photos in the selected album, it should indicate that the page does not exist (404 error). In fact, there is page:

Error
The selected album / file does not exist!

But this is not 404 error!
Therefore, these pages get into Google cache.
How can I do to on the page was a 404 error?

[Αndré]

Why should Coppermine display a 404 error? The file thumbnails.php exist. If you still want to display another message, enable debug mode and track back where the error message is thrown.

[Plazik]

Why should Coppermine display a 404 error? The file thumbnails.php exist. If you still want to display another message, enable debug mode and track back where the error message is thrown.

Because there is no file at this address. This page not found. Therefore, there must be an error 404.