This is one of the worse errors i came across so far, whenever i tried to update my fedora 12 through yum there was an error saying

[Errno 14] PYCURL ERROR 7 – “”
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: fedora. Please verify its path and try again

there were tons of solutions available on googling, but most of them were useless. This is how i worked out the problem

first of all if you are using proxy server,configure your yum.conf file so that you can link to proxy

after that try the following commands

#yum clean all

#yum clean metadata

Now try to update again using yum, even if the same error is coming... it is probably due to  python .

Since the python does not handle https proxy well, change all the https present in *.repo files  in   /etc/yum.repos.d/ to http

Here’s the way to do it… edit your repository files /etc/yum.repos.d/fedora.repo and /etc/yum.repos.d/fedora-updates.repo by commenting all the lines starting with term mirrorlist and uncommenting all the lines starting with term baseurl.

Now append the following to your /etc/hosts file

This worked for me and hopefully it must work for you also. If you want a copy of all *.repos file then  ask in comment.