coqchk: 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/coqchk - from package: coq

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

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