1) Welcome to the Party!
2) As you are obviously new here, I have some suggestions to help us all help you:
When you post, please post your entire configuration including (but not limited to) your installation method (7.X.X?) and vicidial version with build (VERSION: 2.X-XXXx ... BUILD: #####-####).
This IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "manual/from scratch" you must post your operating system with version (and the .iso version from which you installed your original operating system) plus a link to the installation instructions you used. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3)
i need to change the audio for agents.
this is not related to the agent alert. In an ingroup notification, the agent is alerted specifically by an audio file injection (because someone paid for this feature, and because it's not time-sensitive: an extra .25 seconds won't be notable during inbound calling).
But for outbound calls, the audio is provided by the Meetme Asterisk Conferencing Application. And it's coded into the module. So you can either turn off the audio entirely and add a function to play an audio file (which will take time, precious time) before passing the client into the session OR you can DROP all the calls to an ingroup and allow them to borrow that code (still a loss of time, but now there's less coding involved).
I don't recommend either, but since I have nothing more to go on than "need to change the audio", I'm out of juice here.