Cannot map a network drive to access a web site

Hi,

I try to use WebDav features to be able to access a web site as a drive in the Windows Explorer. I have already activated WebDav publishing feature in Windows Server 2008 R2 and the Desktop Experiences as well. I have then started the WebClient service but when I try to map a network drive and type the URL I get the error message below, se the attached screen shot.

I have already tried all the tips I found on the net but still cannot map it. I appreciate any suggestion. 

Here is the error message:

Best Regards

//Ashraf