kfontinst: 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/kfontinst - from package: kdebase-workspace

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

On Debian possible default full paths are:

/usr/bin/kfontinst - from package: kde-workspace-bin

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

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