snmptest: 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/snmptest - from package: net-snmp-utils

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

On Debian possible default full paths are:

/usr/bin/snmptest - from package: snmp

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

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