SpecularSpheres: 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/SpecularSpheres - from package: vtk-examples

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

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