gen-texsubimage: 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-texsubimage - from package: piglit

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

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