yum update error

[sandeep Patel]

Hi All,
          I have installed fedora 15(fresh).And when I tried to update
it it gives error like this:
[root at localhost ~]# yum update
Loaded plugins: langpacks, presto, refresh-packagekit
Could not retrieve mirrorlist
http://mirrors.rpmfusion.org/mirrorlist?repo=free-fedora-15&arch=x86_64
error was
14: curl#5 - "Couldn't resolve proxy"
Could not retrieve mirrorlist
http://mirrors.rpmfusion.org/mirrorlist?repo=free-fedora-updates-released-15&arch=x86_64
error was
14: curl#5 - "Couldn't resolve proxy"
Could not retrieve mirrorlist
http://mirrors.rpmfusion.org/mirrorlist?repo=nonfree-fedora-15&arch=x86_64
error was
14: curl#5 - "Couldn't resolve proxy"
Could not retrieve mirrorlist
http://mirrors.rpmfusion.org/mirrorlist?repo=nonfree-fedora-updates-released-15&arch=x86_64
error was
14: curl#5 - "Couldn't resolve proxy"
Error: Cannot retrieve repository metadata (repomd.xml) for
repository: fedora. Please verify its path and try again

I am using my net connection behind proxy server. So I also made the
changes in yum.conf file for proxy, proxy_username,proxy_password.

Could any one please help to come out from this problem.

--
Sandeep Kumar Patel
M.C.A.
University of Hyderabad
Email ID: leosandeep08 at gmail.com
Contact N0.: +91-9491383752