Keeping those pesky Linux guests at the correct time when playing around with snapshots on VMware can be a bit of a headache as NTP will refuse to play if the server time is much different to the time provided by the NTP server.
To get around this simply add
tinker panic 0
to ntp.conf. This means the ntp daemon will always use the NTP server’s time regardless of how “wrong” it appears to the Linux OS. This means, when restoring snapshots, the time will always get back in sync.
VMware have a useful article in their knowledge base here: Timekeeping best practices for Linux guests