pammixinterlace: 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/pammixinterlace - from package: netpbm-progs

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

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