mpiman: 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/lib64/mvapich-psm/bin/mpiman - from package: mvapich-psm
/usr/lib64/mvapich/bin/mpiman - from package: mvapich
/usr/lib/mvapich/bin/mpiman - from package: mvapich

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

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