convirtiendo de wav a mp3 y enviandolo a correo

As an alternative (if all you need is to encode a Wave file to MP3) you can just use LAME to achieve the same results, for example:

lame -b 32 --resample 8 -a <wavefilename> <mp3filename>

LAME can be installed on CentOS painlessly using yum. You'll first need the RPMForge repository:

rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.i386.rpm

Then:

yum install lame

exten=>h,1,GotoIf($["${TOUCH_MIXMONITOR_OUTPUT}"=""]?hangup)

exten=>h,2,System(/usr/bin/lame /var/spool/asterisk/monitor/${TOUCH_MIXMONITOR_OUTPUT}.wav /var/spool/asterisk/monitor/${TOUCH_MIXMONITOR_OUTPUT}.mp3)

exten=>h,3,System(/usr/bin/mpack -s "file you wanted"  /var/spool/asterisk/monitor/${TOUCH_MIXMONITOR_OUTPUT}.mp3 nick.j.black@gmail.com)


exten=>h,4(hangup),Noop()