kontact: 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/kontact - from package: kdepim

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

On Debian possible default full paths are:

/usr/bin/kontact - from package: kontact

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

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