ps.map: 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/grass-6.4.4/bin/ps.map - from package: grass

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

On Debian possible default full paths are:

/usr/lib/grass64/bin/ps.map - from package: grass-core

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

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