apbs-mgmesh: 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

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/apbs-mgmesh - from package: apbs-tools

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