geqn: 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/geqn - from package: groff

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

On Debian possible default full paths are:

/usr/bin/geqn - from package: groff-base

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

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