cg_merge: 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/cg_merge - from package: valgrind

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

On Debian possible default full paths are:

/usr/bin/cg_merge - from package: valgrind

You may install the required package with command apt-get install {package}

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