clamd: 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/sbin/clamd - from package: clamd

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

On Debian possible default full paths are:

/usr/sbin/clamd - from package: clamav-daemon
/usr/lib/debug/usr/sbin/clamd - from package: clamav-dbg

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

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