I've just installed ZC 1.5 on a new host and everything seems to have gone well except that since renaming the admin folder I am unable to access admin, the page displaying:

'Not Found
The requested URL /****/ was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.'

Now I must admit to being fairly new to all this and thought I'd learn by trial-and-error, but I cannot seem to get past this. Any help would be much appreciated.