Can't upload a file

I am trying to make my website more cell phone friendly. But when I try to upload this particular file I get this warning:

"Forbidden

You don't have permission to access /Fishes.htm on this server."

I can upload any other file - the most recent of which is www.ryanphotographic.newsyngnathidae.html

But if I scroll to the end of the page and click on the link "Fishes" the same error code shows up.

When I try and upload "Fishes.htm" and ask for an upload of associated files they all upload successully and then Dreamweaver tells me that Fishes.htm did not upload.

I blunder my way through Dreamweaver so am basically an amateur.

Confused, frustrated and alarmed - thanks to anyone who can help.