I would like to redirect clients from all IP's except my IP to the Error page eg. Not found error 404.
Use AccessList to arange the access and use the ErrorHandler (for 403) to print a not found message.
It has to look as realistic as possible.
Use a CGI script for the ErrorHander and let it output a 404 HTTP error code instead of a 403.
In my case it must look like this. http://www.mysite.com/site/secret/.... All the things whats coming after secret, must redirect to the error site.
I don't understand what you mean by this. 'error site'?