obrotate: 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/obrotate - from package: openbabel

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

On Debian possible default full paths are:

/usr/bin/obrotate - from package: openbabel

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

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