chktex: 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 Debian possible default full paths are:

/usr/bin/chktex - from package: chktex

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

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