Queue sound files have to follow this naming convention:

GREETING

  'queue-greeting-$NAME.gsm' 

PERIODIC ANNOUNCEMENT

  'periodic-announce-$NAME.gsm' 

AGENT-ANNOUNCE

  'agent-announce-$NAME.gsm' 

QUEUE CALLBACK CALLER AND AGENT ANNOUNCE  

'qc-announce-caller-announce-$NAME.gsm'  'qc-announce-agent-announce-$NAME.gsm'