gencmn: 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/sbin/gencmn - from package: icu

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

On Debian possible default full paths are:

/usr/sbin/gencmn - from package: icu-devtools

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

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