Theme import error

I get an error when importing theme. I said, we encounter an error page after you install a theme that ...permission settings, such is not an anomaly
The error as follows
"Forbidden

You don't have permission to access /acp/index.php on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."

Quote from Black Rider

It looks like a wrong configuration of the suhosin extension of the server.

How to avoid this error, remove