ksnapshot: 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/ksnapshot - from package: kdegraphics

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

On Debian possible default full paths are:

/usr/bin/ksnapshot - from package: ksnapshot

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

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