[CentOS] YUM update from RHEL3 to CentOS3 stalls

Hi all,

I just ran into a problem. I was following the nifty procedure to 
upgrade a WhiteHat/RHEL3.x box to CentOS 3.6 and the update hung. It 
was in the process of updating
MySQL server, and a post install scriptlet apparently failed. So I 
killed the process
with a CTRL-C. However, upon trying to restart YUM, it says there is 
nothing left to,
saying:

Gathering header information file(s) from server(s)
Server: CentOS-3 - Addons
Server: CentOS-3 - Base
Server: CentOS-3 - Extras
Server: CentOS-3 - Updates
Finding updated packages
Downloading needed headers
No Packages Available for Update
No actions to take

However, the MySQL server package was 121/172, so there should be 51 
packages
left. Unless the output to the screen was killed off, but the process 
continued?

I have yet to reboot for fear something is in a very unstable state.

Any ideas?

Thanks,

Ian