recently i installed an ubuntu server, but it doesn't supported GUI, one of my friends suggested to Use this code to install xfc GUI, 'sudo apt-get update && sudo apt-get install xubuntu-desktop' but as i typed this codes i understood that i have some more problems in my installation, the ubuntu respose was:

"w: failed to fetch http://ir.archive.ubuntu.com/ubuntu......gz something wicked happened resolving 'my proxy and port number' (-5- no address associated with host name)"

ubuntu reapeated such massages several times and then it displayed:

"E: some index files failed to download, they have been ignored or old ones used instead"

can anyone help me with this?

Have you tried main servers?
delete "ir." in your sources list

how can i select main servers?

Check the Ubuntu Forums, that might help.

But I'm really curious, why do you want a GUI on a server ?

It's much easier to install "desktop" Ubuntu and then install the packages you need for the server, which can be easily done with the synaptic package manager. I use my desktop Kubuntu as a FTP and SVN server and it works fine.

Yep, That would be my question (and experience), too. ?

Are you you able to install other apps on the server that do not require a huge list of prerequisites without errors?