coq_makefile: 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/coq_makefile - from package: coq

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

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