clamav-config: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/clamav-config - from package: clamav-devel

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/clamav-config - from package: libclamav-dev

You may install the required package with command apt-get install {package}

Error in other languages:
clamav-config: bevel nie gevind nie
clamav-config: comandă negăsită
clamav-config: comando não encontrado
clamav-config: commande introuvable
clamav-config: command not found
clamav-config: käsku ei ole
clamav-config: không tìm thấy lệnh
clamav-config: komanda nerasta
clamav-config: Kommando nicht gefunden.
clamav-config: kommandot finns inte
clamav-config: komut yok
clamav-config: nie znaleziono polecenia
clamav-config: níor aimsíodh an t-ordú
clamav-config: no se encontró la orden
clamav-config: no s'ha trobat l'ordre
clamav-config: opdracht niet gevonden
clamav-config: parancs nem található
clamav-config: perintah tidak ditemukan
clamav-config: príkaz nenájdený
clamav-config: příkaz nenalezen
clamav-config: команда не найдена
clamav-config: командата не е открита
clamav-config: 命令找不到
clamav-config: コマンドが見つかりません