mktexfmt: 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/mktexfmt - from package: texlive

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

On Debian possible default full paths are:

/usr/bin/mktexfmt - from package: texlive-base

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

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