Fernanda, faz assim:
[tiago@MAQ711 tiago]$ su -
Password:
[root@MAQ711 root]# sndconfig
-bash: sndconfig: command not found
[root@MAQ711 root]# up2date sndconfig
Fetching package list for channel: redhat-linux-i386-8.0...
########################################
Fetching Obsoletes list for channel: redhat-linux-i386-8.0...
########################################
Fetching rpm headers...
Testing package set / solving RPM inter-dependencies...
########################################
sndconfig-0.69-1.i386.rpm: ########################## Done.
sox-12.17.3-7.i386.rpm: ########################## Done.
aumix-2.7-12.i386.rpm: ########################## Done.
Preparing ########################################### [100%]
Installing...
1:sndconfig ########################################### [100%]
2:sox ########################################### [100%]
3:aumix ########################################### [100%]
The following packages were added to your selection to satisfy dependencies:
Name Version Release
--------------------------------------------------------------
sox 12.17.3 7
aumix 2.7 12
Heheheh... mas vendo seu outro post percebi que ainda não tem conexão com a NET, né?
Então procura nos seus CD's, um pacote chamado sndconfig-algumacoisa.rpm e clica nele para instalar