CentOS 4.4 upgrade to CentOS 5

During start transaction, hit the error message : installation failed due to the follwing reason (no reason it is shown, instead it is blank).

What I did are:
1. Remove unnecessary repository from /etc/yum.repo.d .
2. Free up disk space (/) to 11Gb. (Think it was due to this reason,as failed twice when free space was <6Gb)
3. Tried to upgrade in text mode.

Don't know which of above is the exact cause/solution, anyway it suceed after near four hours upgrade.


After that, need the folloings to make live udpate available.

cd /etc
cp yum.conf.rpmnew yum.conf
cd /etc/yum.repos.d
cp CentOS-Base.repo.rpmnew CentOS-Base.repo

Cheers.

References:
http://www.linuxfans.org/bbs/redirect.php?tid=178447&goto=lastpost&highlight=