coqchk.opt: command not found

Have You tried accessing the binary with the full path?

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.opt - from package: coq

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