kcolorchooser: 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/kcolorchooser - from package: kdegraphics

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

On Debian possible default full paths are:

/usr/bin/kcolorchooser - from package: kcolorchooser

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

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