rosinstall: 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/rosinstall - from package: python-rosinstall

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

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