voro++: command not found

Have You tried accessing the binary with the full path?

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/voro++ - from package: voro++

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