Problem Comedian Voicemail

Asterisk 1.8, Ubuntu 11.04 - hosted at Rackspace

My Comedian voicemail OGM for some reason gets played incomprehensibly garbled/excessivley choppy, and sometimes clear.
I don’t have a problem generally with call/line quality, certainly nothing like this.
Any ideas?
Just some help in where to go to try and diagnose the issue would help, I don’t know where to start…

Assuming you are not trying to use a VM, you probably have no suitable internal timing source configured.

Thank you for your suggestion. I’ve been so stuuupid, I found the real cluprit, this happened before…just shows I need a better library of solutions.
The answer was that my backup Asterisk server had fired up! Two asterisk servers playing the same message a little out of sync!

I don’t believe Asterisk is designed to be used in a configuration where that would be possible!