gen-teximage: 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/gen-teximage - from package: piglit

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

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