No Ringing Tone after Upgrade to R10

[fys]

Hello guys. I hope someone could help me. I am facing a problem while upgrading a site.
The upgrade is from R6.2 to R10.
After the upgrade, caller cannot hear any Ringing Tone. Will only know the call went through when the other side picks up the call.
The site is using FR database.
I check from technical doc that Tone 27 is the ringing tone, but when I use Tone Test to listen, Tone 27 is just silent.
How else can I rectify this prob? Anyone has a solution?

Thanx.

[fys]

Hi. Problem is solved. It's due to corrupted tone files. Reloading the CPU solves the prob.