mktexmf: 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/mktexmf - from package: texlive

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

On Debian possible default full paths are:

/usr/bin/mktexmf - from package: texlive-binaries

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

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