while i would love to help directly ... there is a reason CentOS is neither supported nor recommended. Very few people have succeeded in getting VICIdial completely "up and running" on CentOS (gardo is a very special guy!).
You should consider either GoAutoDial or Vicibox or Vicibox Redux.
OR you could try the Vicibox DEMO CD. It does not require installation. Capture the output of your asterisk debug and your agi debug (/var/log/asterisk, controlled by /etc/asterisk/logger.conf and /var/log/astguiclient controlled by admin->servers->logging) on your production server, and then compare to the Demo CD for a similar call.
MY Advice would be a stock install after spending more than an hour trying to resolve it (because stock install takes under an hour for us ...
)
Also: If you install Vicibox Redux 3.0.6 ... you'll get the latest stock system with the latest VICIdial with a LOT more toys and gadgets (custom fields? call filtering? call menus?)