snmpcheck: 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/snmpcheck - from package: snmpcheck

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

On Debian possible default full paths are:

/usr/bin/snmpcheck - from package: snmp

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

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