glpsol: 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/glpsol - from package: glpk-utils

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

On Debian possible default full paths are:

/usr/bin/glpsol - from package: glpk-utils

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

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