I've just got the same problem today. I didn't have this message for about a week since my install, but today I installed asp on my webhosted server because my hosts (fasthosts.co.uk) said I'd need to do that to enable cURL for paypal payments. So now when I go to my ZC site I have the red banner saying that my configure.php can be written to.

I tried to change permissions in flashfxp but nothing changes when I change the chmod number or check the check boxes to change to read only.
I tried to set the file in windows to read only which works in windows but when i upload to the server the permissions have reset back to 700.

I asked my hosts if I could change the permissions in control panel but they said I had to close this account and put it onto their Linux servers.

Does that sound right?

Thanks for any advice.

Steven