Doesn’t like copy and paste…

Hello there, This might sound really silly or rather strange but i been having problem all day and i don’t understand it.

ok when i create a new page on my site: https://wwww.misscutie.com – i can create a new page easily enough. but when i copy paste (ctrl v) a content that i want to use – it come up with this:

Forbidden
You don’t have permission to access /wp-admin/post.php on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/1.3.36 Server at https://www.misscutie.com Port 80

I can just write an entry and no problem but i need to put in an entry that i copy and paste and it won’t let me.

Why and help me please…