Put "clock=pit" in the entry for your o/s in the grub.conf file and that should fix the problem. Note that you need to make the change to the entry that's actually being booted. I'm running vmware, and this fixed my problem, even without installing vmware tools. Here's my grub.conf file:
=============================================
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/main/root
# initrd /initrd-version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.9-34.0.2.EL)
root (hd0,0)
kernel /vmlinuz-2.6.9-34.0.2.EL ro root=/dev/main/root clock=pit
initrd /initrd-2.6.9-34.0.2.EL.img
title CentOS (2.6.9-34.0.2.ELsmp)
root (hd0,0)
kernel /vmlinuz-2.6.9-34.0.2.ELsmp ro root=/dev/main/root
clock=pit
initrd /initrd-2.6.9-34.0.2.ELsmp.img
title SME Server (2.6.9-34.ELsmp)
root (hd0,0)
kernel /vmlinuz-2.6.9-34.ELsmp ro root=/dev/main/root
initrd /initrd-2.6.9-34.ELsmp.img
title SME Server-up (2.6.9-34.EL)
root (hd0,0)
kernel /vmlinuz-2.6.9-34.EL ro root=/dev/main/root
initrd /initrd-2.6.9-34.EL.img