scangui: 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/scangui - from package: kipi-plugins

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

On Debian possible default full paths are:

/usr/bin/scangui - from package: kipi-plugins

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

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