pamperspective: 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/pamperspective - from package: netpbm-progs

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

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