Problem with running 'yum update' on my CentOS VPS

[dealspiggy]

I have a VPS with CentOS 5.2, however, I have this error when running 'yum update' through Putty:

Loading "fastestmirror" plugin
Determining fastest mirrors
* utterramblings: www.jasonlitka.com
Could not retrieve mirrorlist http://mirrorlist.centos.org/?releas...h=i386&repo=os error was
[Errno 12] Timeout: <urlopen error timed out>
Error: Cannot find a valid baseurl for repo: base

Below is the content of my /etc/yum.conf

[main]
cachedir=/var/cache/yum
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
distroverpkg=redhat-release
tolerant=1
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1

# Note: yum-RHN-plugin doesn't honor this.
metadata_expire=1h

# Default.
# installonly_limit = 3

# PUT YOUR REPOS HERE OR IN separate files named file.repo
# in /etc/yum.repos.d

Does anyone happen to know what might be wrong? thanks

[topdog]

It looks like outbound connections to http servers have been blocked.