on VM Pro 4.06 Pro
[root@blahblah]# yum install mercurial
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.einstein.yu.edu
* extras: mirror.trouble-free.net
* updates: centos.mirror.nac.net
Setting up Install Process
No package mercurial available.
Nothing to do
However, on another VM host (GPL) it was able to install fine.