scissor-copypixels: 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/lib64/piglit/bin/scissor-copypixels - from package: piglit

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

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